GMAT Problem Solving : Number Properties

This question is an interesting Number Properties Problem Solving GMAT prep question .

How many digits does the product of 4¹² and 5²³ contain?
A. 12
B. 13
C. 23
D. 24
E. 35

The correct answer is choice D.

We can rewrite the given numbers as 2²⁴ * 5²³.
i.e., 2 * 2²³ * 5²³
= 2 * 10²³.
This is a 24 digit number.