Problem:
What is the value of
a2a−1+2a−1​​
when a=21​ ?
Answer Choices:
A. 1
B. 2
C. 25​
D. 10
E. 20
Solution:
21​2(21​)−1+2(21​)−1​​=(2⋅2+22​)⋅2=10​
The problems on this page are the property of the MAA's American Mathematics Competitions