hansoo wrote:In the below addition a, b, c, d, e and f each represent a digit. What is the value of a + b + c + d + e + f ?
(1) At least three of the digits are greater than 3.
(2) be = 24
(1) we can pick multiple sets of numbers to make this work, for example: 444+556 or 450+550. In the first case the digits sum to 28; in the second they sum to 19. Insufficient.
(2) If b and e are digits with a product of 24, they must be 3/8 or 4/6.
If they were 3/8, then they sum to 11; there would be no way to get a "0" in the summation as the second last digit in that case. Therefore, b and e must be 4/6.
If b and e are 4/6 and must produce a "0" underneath, then we can't carry anything over from the right column. Accordingly, c and f must be 0 and 0.
We know that when we add b and e, we'll carry a 1 over to the left column. Therefore, a+c must equal 9 to produce "10" in the summation.
So:
a+c=9
b+e=10
d+f = 0
a+b+c+d+e+f = 19... sufficient.
(2) is sufficient, (1) isn't: choose B.
