GMAT Practice Question: If a > 0, b = 2a, and c = 2b, which of the following is equivalent to a^b b^c ?
Question
If a > 0, b = 2a, and c = 2b, which of the following is equivalent to a^b b^c ?
- (2a^4)^a
- (2a^6)^a
- (2a^8)^a
- (16a^6)^a
- (16a^8)^a
Topics: exponents, expression formulas
Solution
Step 1
We first express the given relationships of b and c in terms of a
b = 2a c = 2b
Step 2
We substitute these expressions for b and c into a^b b^c
a^b b^c = a^2a (2a)^4a
Step 3
We expand (2a)^4a by raising each factor to the power 4a
(2a)^4a = 2^4a a^4a
Step 4
We apply Multiplying Exponents of the Same Base to combine a^2a and a^4a
a^2a a^4a = a^2a + 4a = a^6a
Step 5
We rewrite 2^4a and a^6a using Exponents of Exponents and combine them
2^4a = (2^4)^a = 16^a a^6a = (a^6)^a 2^4a a^6a = (16 a^6)^a
Answer
D
