Og Problems

Front 1

100. On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of 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
(D) 5^10
(E) 8^10 - 3^10

Back 1

The question asks 8 is how many times greater than the intensity of 3. It is 5 times greater since 8 -3 = 5.

Each intensity value is 10 times greater than the previous intensity. So if the difference between the two intensities is 5 times, then 10 x 10 x10 x 10 x 10 = 10^5

Answer is C

Front 2

A certain country had a total annual expenditure of $1.2 x 10^12 last year. If the population of the country was 240 million last year, what was the per capita expenditure?

$500
$1000
$2000
$3000
$5000

Back 2

annual expenditure / population
note that the population is in millions and you must account for 6 zeroes

(1.2 x 10^12)/(240 x 10^6)

simplify to:

(12 x 10^11) / (24 x 10^7)

= 12/24 = 0.5

11- 7 = 4

0.5 x 10^4 = 5000

Front 3

176. The positive integer n is divisible by 25. If √n is greater than 25, which of the following could be the value of n/25?

22
23
24
25
26

Back 3

N/25
√n >25
so n>25^2

so the answer must be greater than 25. the only answer choice greater than 25 is 26

E