Bunuel wrote:
If n is a two-digit number, in which n = x^y. If x + y < 8, and x and y are positive integers greater than one, then the units digit of n could be which of the following?
I. 5
II. 6
III. 7
A. I only
B. II only
C. III only
D. I and III only
E. I, II and III
n is a two digit number, let's see if we can form a two digit number by x^y when x+y<8
Let's try to get 5 in unit digit= 5^2, possible. 5+2<8
Let's try to get 6 in unit digit= 2^4, possible. 2+4<8
Let's try to get 7 in unit digit= 3^3, possible. 3+3<8
E, all I II and III possible.
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