Question

If (2a)(2b)=128, what is a + b equal to?

A.) 1
B.) 6
C.) 7
D.) 12

Answer 1

Alright so we have 4ab = 128 or ab = 32
Now what are the perfect factors of 32? [1x32,2x16,4x8]
We obviously can eliminate 1
Even 6 cannot be the answer because there are no factors which add upto 6
And thus even 7 can be eliminated!
Leaving us with 12 [8+4]
Thus 'a' can be 4 or 8 and 'b' can be 8 or 4 respectively.
Just be reminded that there is not any actual method to give us the answer!
ELIMINATE! :D

Answer 2

Soo it's 1 ?

Answer 3

See we have to find A + B
WHICH HAS TO BE 12
All the actual possible values of
A+B are = 33 {1 x 32} or 18 {16 x 2} or 12 {4x8} [ AxB = 32 right? that's why ]
And 12 is a value in the answer so the answer is D) 12 :)

Answer 4

Alright, thanks (:

Answer 5

Kudos?