Can we backsolve this question basis answer choices please?

Brent@GMATPrepNow wrote:

[email protected] wrote:Each digit in the two-digit number G is halved to form a new two-digit number H. Which of the following could be the sum of G and H?

A. 153
B. 150
C. 137
D. 129
E. 89

IMPORTANT: If we're going to halve each digit to get two new digits, the two original digits MUST BE EVEN.

So, the LARGEST possible 2-digit number (with EVEN digits) is 88
If we halve each digit, we get 44
88 + 44 = 132
So, the largest possible SUM is 132.
This means we can ELIMINATE A, B and C

Now let's check the remaining answer choices.
Answer choice D (129), is very close to the largest possible sum (132) that we just calculated. So, let's fiddle with those numbers to see whether we can get a sum of 129

How about 86? (the 2nd largest value for the original number)
If we halve each digit, we get 43
86 + 43 = 129 . . . we have a MATCH

So, the correct answer must be D

Cheers,
Brent