Ice Cream, You Scream – Answer
The two numbers are 1 and 5.
The following are the possible numbers that would give Alpha a unique result to “a * b”, assuming the two numbers are different and neither is zero:
1-2, 1-3, 1-4, 1-5, 1-7, 1-9, 2-5, 2-7, 2-8, 3-5, 3-7, 3-9, 4-5, 4-7, 4-8, 4-9, 5-6, 5-7, 5-8, 5-9, 6-7, 6-8, 6-9, 7-8, 7-9, 8-9.
Of the above groups, the following would give Beta a unique result to “a + b”:
1-2, 1-3, 1-4, 1-5, 2-5, 7-9, 8-9.
Of the above groups, the following would give Charlie a unique result to “b – a”:
1-5
Delta is given the result of “((1 + 5) + (5 – 1)) / (1 * 5)” which is 2. Delta didn’t even need this result, as Charlie’s “yes” answer left only the one possibility, anyway.
Yum, Yum. Blueberry, Cookie-Dough, Mint-Chip ice cream sundaes.
(Unfortunately, the Garlick’s taste in ice-cream flavors wasn’t as astute as their logic skills.)