bakfed wrote:

The value of (9x10^7)(9x10^8) is closest to which of the following?

A. 10^16

B. 10^17

C. 10^56

D. 10^57

E. 10^58

We can simplify the given expression.

(9 x 10^7)(9 x 10^8) = 9^2 x 10^15

We can immediately eliminate answer choices C, D, and E since powers of 10 in the order of 56, 57, or 58 is nowhere near the order of 15. We only need to decide between answer choices A and B. We note that 9^2 = 81 is closer to 100 than to 10; therefore, of the provided answer choices, 9^2 x 10^15 is closest to 10^17.

Answer: B

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