Bunuel wrote:
If a, b, c, and d denote positive integers in the figure above, what is the value of the product abcd ?
(1) In each of columns S and T, the product of the three numbers equals the product of the four numbers in row R.
(2) a + b + c + d = 26
DS20356
Given: a, b, c, and d denote positive integers in the figure above Target question: What is the value of the product abcd ? Statement 1: In each of columns S and T, the product of the three numbers equals the product of the four numbers in row R. The product of the four numbers in row R = (2)(3)(4)(5) =
120So, from column S, we can write: (a)(3)(c) =
120Divide both sides of the equation by 3 to get:
ac = 40So, From column T, we can write: (b)(4)(d) =
120Divide both sides of the equation by 4 to get:
bd = 30So, abcd = (
ac)(
bd) = (
40)(
30) =
1200Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: a + b + c + d = 26There are several values of a, b, c, and d that satisfy statement 2. Here are two:
Case a: a = 1, b = 1, c = 1 and d = 23. In this case,
abcd = (1)(1)(1)(26) = 26Case b: a = 3, b = 3, c = 10 and d = 10. In this case,
abcd = (3)(3)(10)(10) = 900Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
Cheers,
Brent
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