BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Intensity Question

Expert replies
by sanchu » Mon Feb 10, 2014 4:00 pm
On a scale that measure the intensity of a certain phenomonenon, a reading of n+1 corresponds to the intensity that is 10 times the intensity corresponding to a reading o n. On that scale the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3?

a) 5
b)50
c) 10^5
c)5^10
d) 8^10-3^10
Join the discussion
Source: — Problem Solving |

by Bill@VeritasPrep » Mon Feb 10, 2014 4:08 pm
sanchu wrote:On a scale that measure the intensity of a certain phenomonenon, a reading of n+1 corresponds to the intensity that is 10 times the intensity corresponding to a reading o n. On that scale the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3?

a) 5
b)50
c) 10^5
c)5^10
d) 8^10-3^10
I did a quick table of values:

reading of 1 = 1
reading of 2 = 10
reading of 3 = 10^2
reading of 4 = 10^3
reading of 5 = 10^4
reading of 6 = 10^5
reading of 7 = 10^6
reading of 8 = 10^7

The difference between the exponents is 5: 10^2 * 10^5 = 10^7. Go with C.
Join Veritas Prep's 2010 Instructor of the Year, Matt Douglas for GMATT Mondays

Visit the Veritas Prep Blog

Try the FREE Veritas Prep Practice Test
Join the discussion

by [email protected] » Tue Feb 11, 2014 12:32 am
Hi sanchu,

Bill has correctly explained the logic behind the prompt. I'm going to present the information in a slightly different way (using the vocabulary the prompt uses):

Let's say that the "first level" of a phenomenon is N.

So, the "second level" would be 10 times the "first level" = 10N
The "third level" would be 10 times the "second level" = 10(10N) = 100N
The "fourth level" would be 10 times the "third level" = 10(100N) = 1,000N
Etc.

The pattern is that each level is "10 times" greater than the prior level. With that pattern, a "reading of 8" relative to a "reading of 3" is a difference of 10(10)(10)(10)(10)N = (N)10^5

Final Answer: C

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Join the discussion