If 5^21 * 4^11 = 2 * 10^n, what is n?
A) 11
B) 21
C) 22
D) 23
E) 32
[spoiler]OA: B[/spoiler]
Thanks much!
A) 11
B) 21
C) 22
D) 23
E) 32
[spoiler]OA: B[/spoiler]
Thanks much!
The right side is 2 * 10^n
5^21 * 4^11 = 2* (5^n * 2^n)
5^21 * ((2)^2)^11 = 2* (5^n * 2^n)
5^21 * 2^22 = 2* (5^n * 2^n)
Divide each side by 2
5^21 * 2^(22-1) = 5^n * 2^n
5^21 * 2^21 = 5^n * 2^n
So n = 21
