Carcass wrote:
If \(27^p*3^2 = 3^4*9^8\), what is the value of p?
A. 3
B. 6
C. 8
D. 15
E. 16
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITIONGRE - Math BookFor equations with a variable in the exponent, it's useful to rewrite both sides of the equation with the SAME BASES.
Here, it appears we can rewrite
27 and
9 sides as powers of 3.
We'll replace
27 with
3^3, and we'll replace
9 with
3^2Given: (
27^p)(3^2) = (3^4)(
9^8)
Replace to get: [(
3^3)^p](3^2) = (3^4)[(
3^2)^8]
Apply power of a power law to get: (3^3p)(3^2) = (3^4)(3^16)
Apply product law to get: 3^(3p +2) = 3^20
Since the bases are equal, we can conclude that 3p + 2 = 20
Solve to get p = 6
Answer: B