Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

You are right, kylekatarn, Very well done!

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

109. How many times the Principal would an amount deposited in a bank paying interest at 10% per annum compounded annually grow to?

110. Which of these would have the greatest volume? A spehere of radius 1 cm, a cube of side 1 cm or a cylinder of height 1 cm and radius 1 cm?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**Toast****Real Member**- Registered: 2006-10-08
- Posts: 1,321

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

And you thought right, Toast! Well done!

111. My mother is three times my age in years. 15 years later, she'd be double my age. What is the age difference between me and my mother?

112. If 1/a, 1/b and 1/c are in Harmonic Progression, what would (a+c)/2 be equal to?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

113. Complete the series...

1, 3, 10, 21, 64, 129, _____, 777.

114. It takes 2 minutes to boil a single egg. How many minutes will it take to boil 5 eggs together?

115. If the fifth of the month falls two days after Monday, what day of the week would precede the nineteenth of the month?

116. If 5 boys write 5 pages in 5 minutes, in how many minutes can one boy write one page?

117. An aeroplane flies twice as fast as a Superfast train runs. The train covers 60 miles in 90 minutes. What distance would the aeroplane cover in 20 minutes?

118. A lady is five years younger than her husband. The husband is 5 times as old as their daughter. If the daughter was 5 years old exactly three years ago, what is the lady's present age?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**kylekatarn****Member**- Registered: 2005-07-24
- Posts: 445

*Last edited by kylekatarn (2007-02-14 06:04:29)*

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

OMG! kylekatarn, The problem does not require such an analysis, and your answer isn't correct!

I shall post the solution after some time! As a matter of fact, the problem is far more simpler, but I understand solving the 'Complete the series' is never easy!

119. Divide a sum of $832 between A and B in the ratio 1/3:1/5.

120. I paid $27.20 as Sales Tax on the sale of a wrist-watch worth $340. What is the rate of the Sales Tax?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**kylekatarn****Member**- Registered: 2005-07-24
- Posts: 445

Lol!;P well, that was the logic I found! a bit complex indeed... I can't wait to see the simple solution!:D

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

Solution to 113:- Complete the series...

1, 3, 10, 21, 64, 129, _____, 777.

Lets name the first term as t1, second as t2, the third as t3 and so on.

t1=1

t2=(t1x2)+1=3

t3=(t2x3)+1=10

t4=(t3x2)+1=21

t5=(t4x3)+1=64

t6=(t5x2)+1=129

t7=(t6x3)+1=(129x3)+1=388

t8=(t7x2)+1=(388x2)+1=777

121. Find the sum of the first 200 terms in the series

1, 5, 9, 13, ................

122. What is the value of

11³+12³+13³+14³+...................19³+20³?

123. What is the value of

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**kylekatarn****Member**- Registered: 2005-07-24
- Posts: 445

ganesh wrote:

Solution to 113:- Complete the series...

1, 3, 10, 21, 64, 129, _____, 777.Lets name the first term as t1, second as t2, the third as t3 and so on.

t1=1

t2=(t1x2)+1=3

t3=(t2x3)+1=10

t4=(t3x2)+1=21

t5=(t4x3)+1=64

t6=(t5x2)+1=129

t7=(t6x3)+1=(129x3)+1=388

t8=(t7x2)+1=(388x2)+1=777

so simple indeed! it's amazing how we sometimes tend to search the complex solutions first;)

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

Yes, kylekatarn, I agree with you.

I remember having read an SMS puzzle (pun intended),

which says, if 1=5, 2=25, 3=125, and 4=625, then 5=?

Instinctively, the credulous reader calculates what 625x5 is,

but the answer is 5=1, because that was what we started with

124. A person travels 2 miles from the starting poing, turns left and travels 3 miles, then turns left again and travels 6 miles. How far is he from the starting point?

125. 1/3:1/4::20x:?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**Toast****Real Member**- Registered: 2006-10-08
- Posts: 1,321

Unless, of course, 1 = 3125

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

126. The slant height of a cone is 26 cm and the diameter of the base is 20 cm. What is its vertical height?

127. What is the value of (2 tan30°)/(1+tan²30°) ?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**kylekatarn****Member**- Registered: 2005-07-24
- Posts: 445

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

Well done, kylekatarn!

128. How many twin Primes exist between 1 and 100?

Note:- 1 is neither prime nor non-prime; 2 and 3 are not twin-primes.

129. How many years does the farthest planet in the Solar System take to go around the Sun once?

130. How many leap years were there in the twentieth century?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Why did the vector cross the road?

It wanted to be normal.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

126 :- You are correct, well done, mathsyperson!

130:- 20th century is 1901 AD to 2000 AD. Would you like to change the answer?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Ah, well in that case

Now that I think about it, that does make more sense.

Using my logic, the first century would have been from 0 to 99AD, but there wasn't a year 0 so that wouldn't have worked.

Why did the vector cross the road?

It wanted to be normal.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

Correct, mathsperson! Good work!

131. The sum of double of a natural number and three

times another natural number is less than 24. If the first natural

number is less than or equal to eight, then what is the highest value of the second natural number?

132. The boys and girls in a school are in the ratio 3 : 7.

25% of the boys and 20% of the girls are scholarship holders.

What per cent of the total students do not get scholarships?

133. Stephen is 7 times as old as his son. 10 years hence,

he would be 3 times as old as his son. What are their present

ages (in years)?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

134. In how many ways can we arrange 6 books on

different subjects, in a shelf?

135. The average of 4 consecutive even numbers is 9. Find the first number.

136. A certain sum of money doubles in 10 years at simple

interest. What is the rate of interest?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**Devantè****Real Member**- Registered: 2006-07-14
- Posts: 6,400

130) This is one of those odd questions. The normal answer would be 27, but then we totally skipped the year 0. That is a year itself. A leap year would start *on* the year 0. If we followed this rule, there would be 25 in the 20th century...

Offline

**michi****Member**- Registered: 2007-02-17
- Posts: 4

135) first number= 6

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

Correct, Devante`. Well done.

Well done, michi! Excellent!

Welcome to the forum!

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,096

137. 2F7 in Hexadecimal is ________ in Decimal.

138. How is 65536 in decimal expressed in Hexadecimal?

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**kylekatarn****Member**- Registered: 2005-07-24
- Posts: 445

*Last edited by kylekatarn (2007-02-18 17:35:32)*

Offline