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#1 Re: Exercises » Play with numbers » 2009-04-26 17:20:49

i have already given a proof to it

#2 Re: Help Me ! » it is solved ..still.. » 2009-04-23 18:37:26

hi jaisy,

won't the ques be

26 - 63 = -1

#3 Re: Exercises » Play with numbers » 2009-04-23 18:26:30

check the solution of manjyome... her only mistake is she found out D as the answer whereas the reqd answer is the sum of digits of D.

one more thing

the number of digits in 'n' is (characteristic of log n) + 1

#4 Re: Exercises » Play with numbers » 2009-04-23 18:17:21

but u have taken from the page the only solution which is ncorrect ..

btw, For your information ...

D = 10

#6 Re: Exercises » few quants problems » 2009-04-22 00:18:28

# 3

Find the smallest number N which has the following properties:
its decimal representation has 6 as the last digit.

If the last digit 6 is erased and placed in front of the remaining digits, the resulting number is four times as great as the original number N.

#8 Re: Exercises » Play with numbers » 2009-04-21 21:09:33

well you dont get my point do you

TRY TO PROVE THAT THE SUM OF DIGITS OF 'D' WILL BE A SINGLE DIGIT NUMBER

in this question you don't even have to find out the values of b,c,d

#9 Re: Exercises » Play with numbers » 2009-04-21 20:54:02

what procedure do you use to find B

#10 Re: Exercises » few quants problems » 2009-04-21 20:19:50

hi bobbym,

very good observation up

and in fact your answer is correct ... smile

I would give a slightly better way

rewrite the equn as

(sin x)^4 - 2 = (sin x)^5 + (cos x)^5

now the max value of LHS is -1
and the min value of RHS = -1

thus if the equation holds true ... both the sides are got to be equal to -1

hence u can come to the solution ...

#11 Re: Exercises » Play with numbers » 2009-04-21 20:16:25

Hi bobbym,

you found out D .... but in the ques you need to find out the sum of digits of D ... which turns out to be 1+0 = 1

i ll give u the last and most important hint:

let E = sum of digits of D

find a way to prove that E would be a single digit number

then u can easily say that E would be 1

reason:
if the digital root of a number is 1 and the number is single digit number ... then the number is got to be 1 smile

#13 Re: Exercises » Play with numbers » 2009-04-21 18:43:15

bobbym wrote:

The sum of the digits of 199 = 19 = 1 because 199 is congruent to 1 mod 9

if A = 199
den b = sum of digits of A = 10 (not 1)

bobbym wrote:

(by expanding this number, I assumed you didn't want to sum it again else B=1 C=1 D=1)

u r absolutely right here ... i didn't want it to sum it again.

bobbym wrote:

This is as far as I follow the problem please provide more guidance.

u r absolutely correct here ... u followed it absolutely correctly...


HINT: Prove that sum of digits of D will be a single digit number

if u find that sum of digits of D will be a two digits number ... then the ans may be one of... 19,28,37,46,55,64,73,82,91
coz all of the above two digit numbers are congruent to 1 under MOD 9 ....

but if the sum of digits of D is a single digit number then the answer will be 1 .... i hope u get wot i say

#14 Re: Exercises » Play with numbers » 2009-04-20 19:31:29

i agree to upto an extent ... but there's a part remaining to be proved ....

HINT : according to ur proof
sum of digits of 199 = sum of digits of 28
or 19 = 10

wink

#15 Re: Help Me ! » Percentages » 2009-04-15 23:16:03

a shortcut :

if the cost decreases 10% i.e. 1/10

the prev it shud have been 1/(10-1) = 1/9 times more than this year


if the cost wud have increased by 1/10

the prev year it shud have been 1/(10+1) = 1/11 times less than this year

wink

#16 Re: Exercises » few quants problems » 2009-04-15 22:26:55

(sinx)^4-(sinx)^5-(cosx)^5 = 2

solve for x

#18 Re: Exercises » Play with numbers » 2009-04-14 23:21:43

there's another way of solving #2

#19 Re: Exercises » Exercise » 2009-04-14 21:07:29

ganesh wrote:

if

,
what is the value of
?

Answer= 0

#20 Re: Exercises » Exercise » 2009-04-14 21:02:53

ganesh wrote:

What is the value of

?

#21 Re: Help Me ! » basic algebra -help! » 2009-04-14 20:39:47

how can u assume that no legs of any animal are broken tongue

#22 Exercises » few quants problems » 2009-04-14 20:19:36

smiyc86
Replies: 10

Milan uses an escalator at the railway station.

If he runs up 8 steps of the escalator, then it takes him 40.0 seconds to reach the top of the escalator.

If he runs up 15 steps of the escalator, then it takes him only 22.5 seconds to reach the top of the escalator.

How many seconds would it take Milan to reach the top, if he did not run up any steps of the escalator at all? Also, how many steps are visible, when the escalator is stationary?

#23 Re: Exercises » Jane’s Exercises III » 2009-04-03 21:04:40

hmm agreed nice spotting .... thanx.... [:)]

#24 Re: Exercises » Play with numbers » 2009-04-03 20:07:24

let us stop this nonsense discussion .... ok mayb i did a mistake ... i dun wanna spoil everybody's mood ... it's just that girl argued without any sense in the another thread that i was really pi$$d off with her ....

#25 Re: Exercises » Play with numbers » 2009-04-03 18:51:18

i never disrespect anyone ... i can understand how u feel ..... u know her for long .... but she took against me for a long tym ... and i respect those ppl who returns the same to me ... as long as i am here in this forum ... she in no way will earn respect back from me .. for example here u were solving the problem ... u didn't have ne issues ... once i told u to read the statements properly ... nd btw ... OR here in no way meant that it can be div by both ... u cannot implicitly arrive to a conclusion of ur own .... she can teach me math ... but can't teach me logic and interpretations ....

and even if i am wrong .... she shud have the MANNERS to tell me .... if she doesn't have ... she better learn it from somewhere

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