Problem Solving_ Exponents

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

mlamaiti2003: Newbie | Next Rank: 10 Posts; Posts: 4; Joined: Mon May 19, 2008 11:32 am; Location: Alexandria, VA

by mlamaiti2003 » Fri Oct 31, 2008 9:52 am

If 4^11 * 5^21= 2 * 10^n; n=?

A. 13
B. 19
C. 21 (correct)
D. 23
E. 32

Please show me an easy way to solve this.

Thank you,

Source: Beat The GMAT — Problem Solving | Fri Oct 31, 2008 9:52 am

Mani_mba: Master | Next Rank: 500 Posts; Posts: 267; Joined: Wed Jul 16, 2008 12:20 am; Thanked: 4 times; Followed by:1 members

by Mani_mba » Fri Oct 31, 2008 10:07 am

4^11 * 5^21
=> 2^22 * 5^21

Makes the powers same !

=> (2^21 * 5^21) * 2
=> 10^21 * 2

n = 21

• Page 1 of 1