If 5^21 x 8^7 = 10^n what is the value of n?  Pick:	A) 26	B) 24	C) 21	D) 28	E) 20
5^21* (2^3)^7 = 10^n   or 5^21* 2^21 = 10^n   or 10^21 =10^n   n=21   21
<result>C</result>
If 5^21 x 8^7 = 10^n what is the value of n?