saswata4s wrote:

If 10^15 – 49 is written as an integer in base 10 notation, what is the product of digits in that integer?

A) 9^13

B) 4* 9^13

C) 5 * 9^13

D) 51* 9^13

E) 5 * 9^14

Let's look for patter

100 - 49 = 51

1000- 49 = 951

10000 -49 =9951

100,000 - 49 = 99951

Notice that it is 9 is always less than number of Zero by 2.

We have 15 zero's, so we get 13 of 9's........9 ^13

Also 5 *1 =5

So finally we get: 5 *9^13

Answer: C

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.

This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links:

Quantitative |

Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.