Walkabout wrote:

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?

(A) $ 500

(B) $1,000

(C) $2,000

(D) $3,000

(E) $5,000

The key to solving this problem is to accurately translate what is being asked to a mathematical expression. We need to determine the “per capital expenditure”. As an expression this is:

(Total annual expenditure)/(Total population)= per capita expenditure

The easiest first step is to express 240 million as a number times a power of 10 since the other number is in this format.

240 million = 240,000,000

Since we have a 24 with 7 zeroes we can write this as:

24 x 10^7

Next, we should adjust 1.2 x 10^12 to make it a more usable number in our expression.

1.2 x 10^12 = 120 x 10^10

We now can solve:

(Total annual expenditure)/(Total population)

(120 x 10^10)/(24 x 10^7)

5 x 10^3

5 x 1,000 = 5,000

Answer E.

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Scott Woodbury-Stewart

Founder and CEO

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