You are not logged in.
#101 2006-10-17 13:51:29
- ganesh
- Moderator
Offline
Re: 10 second questions
Excellent performance, Devante` and mathsyperson,
You are correct.
I wonder how you manage to do it in under 10 seconds.
54. What is the volume of a room of length 12 feet, breadth 12 feet and height 12 feet?
55. How many square meters is a hectare?
Character is who you are when no one is looking.
#102 2006-10-17 16:10:22
- Devantè
- Real Member
Offline
Re: 10 second questions
54. 1728
55. There are 10,000 square meters in a hectare.
#103 2006-10-17 17:41:12
- ganesh
- Moderator
Offline
Re: 10 second questions
YOU ARE ABSOLUTELY RIGHT, DEVANTE`.
Character is who you are when no one is looking.
#104 2006-10-17 17:45:49
#105 2006-10-17 17:48:09
- ganesh
- Moderator
Offline
Re: 10 second questions
NO................................................
All the calculations should be done by the brain 
Character is who you are when no one is looking.
#106 2006-10-17 17:51:09
- ganesh
- Moderator
Offline
Re: 10 second questions
56. What is sin²360° + cos²360° ?
57. What are the prime factors of 1001?
58. Is 4096 a perfect square?
59. How much percentage is 4 greater than 3?
60. What is the value of 2^10?
Character is who you are when no one is looking.
#107 2006-10-17 22:42:22
- mathsyperson
- Moderator
Offline
Re: 10 second questions
56. 1, just like any other sin² + cos² thing. In this case it's even easier though, because it's just 0 + 1.
57. 11 and 91. You can recognise that it's a multiple of 11 with the nifty trick I used before, and then divide by 11 to get the 91.
58. 4096 = 2^12 = (2^6)² = 64². So yes. I know my powers of 2 too well. 
59. (4-3)/3 x 100% = 33.333...%
60. 2^10 = 1024.
Why did the vector cross the road?
It wanted to be normal.
#108 2006-10-18 01:54:32
- Devantè
- Real Member
Offline
Re: 10 second questions
56. 1
57. 11 and 91 - That's what I got, at least
58. 4096. I have studied the doubling of numbers (especially 2) for a long time. Didn't have to think much
59. 33.333....(recurring)
60. 1024 (I know my doubles and exponents of 2 
)
#109 2006-10-18 13:57:47
- ganesh
- Moderator
Offline
Re: 10 second questions
Devante`and mathsy,
Your answers are all correct.
I wonder whether you use a calculator.
The prime factors of 1001 are 7, 11, 13.
Very well done, Devante`!
Character is who you are when no one is looking.
#110 2006-10-18 14:14:06
- ganesh
- Moderator
Offline
Re: 10 second questions
61. If 12 numbers is a dozen, what is 12 dozens?
62. What is the significance of 9.8 m/s² ?
Character is who you are when no one is looking.
#111 2006-10-18 16:20:42
- Devantè
- Real Member
Offline
Re: 10 second questions
ganesh wrote:
Devante`and mathsy,
Your answers are all correct.
I wonder whether you use a calculator.
The prime factors of 1001 are 7, 11, 13.
Very well done, Devante`!
No, no calculators. I solve them in my head. Sometimes I say the working out to myself.
61. 12^2 = 144, simple tables
62. To convert between units of force and mass, we need to know the strength of gravity. Usually this is the so-called standard gravity (approximately 9.8 m/s² or 32 ft/s²).
To extend on question 62:
Plugging this value into Newton's second law, F = ma (force = mass × acceleration), we see that a one-kilogram mass experiences a gravitational force of 1 kg × 9.8 m/s² = 9.8 newtons. In general, to convert mass in kilograms to force in newtons (at the earth's surface), multiply by 9.8. Conversely, to convert newtons to kilograms divide by 9.8. (32 is the conversion factor for US Customary Units).
#112 2006-10-18 19:43:49
- mathsyperson
- Moderator
Offline
Re: 10 second questions
Oh, boo. I can't believe I forgot to split 91. That's annoying. Ah well.
And I agree with both of Devanté's most recent answers. I know my squares almost as much as I know by powers of 2, and I had to use the 9.8 one very frequently for about 2 years of a mechanics course, so I'm not about to forget it.
Why did the vector cross the road?
It wanted to be normal.
#113 2006-10-19 00:46:21
#114 2006-10-19 13:56:25
- ganesh
- Moderator
Offline
Re: 10 second questions
61. 12 dozens is a gross.
62. 9.8 is the acceleration due to gravity. You are right, Devante` and mathsyperson, this is often used in mechanics.
Character is who you are when no one is looking.
#115 2006-10-19 16:28:16
- Devantè
- Real Member
Offline
Re: 10 second questions
For #61, I wasn't sure which you wanted, twelve dozen as a number of gross.
#116 2006-10-19 18:26:48
- ganesh
- Moderator
Offline
Re: 10 second questions
63. What are the prime factor(s) of 256?
64. What is the value of 7 x 7 x 7?
Character is who you are when no one is looking.
#117 2006-10-19 21:28:57
- mathsyperson
- Moderator
Offline
Re: 10 second questions
63. 256 = 28. Yay for powers of 2!
64. 343. Yay for cubes!
Why did the vector cross the road?
It wanted to be normal.
#118 2006-10-20 01:02:35
- Devantè
- Real Member
Offline
Re: 10 second questions
63. 2^8
64. 343; knew off by heart
(Powers of 2! or 2? )
#119 2006-10-20 01:17:25
- mathsyperson
- Moderator
Offline
Re: 10 second questions
I had a feeling that someone would go pedantic on me. But 2! = 2 so it doesn't matter so ha.
Why did the vector cross the road?
It wanted to be normal.
#120 2006-10-20 16:21:21
- Devantè
- Real Member
Offline
Re: 10 second questions
Yes, I love to comment on typos.
At least there isn't a value for '2?'. Or, as far as I know.
Also, 2! = two!?
#121 2006-10-22 13:25:11
- John E. Franklin
- Star Member
Offline
Re: 10 second questions
Is the special number 26 from Avogadro's number?
Imagine for a moment that even an earthworm may possess a love of self and a love of others.
#122 2006-10-24 14:10:31
- ganesh
- Moderator
Offline
Re: 10 second questions
No, John.
26 is the only number jammed between a perfect square (25) and a perfect cube (27). I had read this somewhere but I don't know how that can be proved.
Avogadro Number is roughly 6.023x10^23.
Character is who you are when no one is looking.
#123 2006-10-25 14:19:13
- ganesh
- Moderator
Offline
Re: 10 second questions
65. What is 2^20?
66. How many prime factors are there in 729?
Character is who you are when no one is looking.
#124 2006-10-25 17:04:19
- Devantè
- Real Member
Offline
Re: 10 second questions
65. 1048576 (a long time ago, we had a competition to see who could get the farthest in doubling from 1 in 2 minutes, plus knowing doubles)
66. 729 = 3x3x3x3x3x3
#125 2006-10-31 00:57:45
- ganesh
- Moderator
Offline
Re: 10 second questions
Devante`,
Thats absolutely remarkable performance.
67. How many prime factors does 7776 have?
68. Whats the value of 7!?
Character is who you are when no one is looking.