Bunuel wrote:
The number N is 532H, the unit's digit being represented by H. What is the value of H?
(1) N is divisible by 3.
(2) N is divisible by 5.
Given: The number N is 532H, the unit's digit being represented by H.Target question: What is the value of H? Statement 1: N is divisible by 3. Key property: If a number is divisible by 3, then the sum of its digits must be divisible by 3This means 5+3+2+H is divisible by 3.
In other words, 10 + H is divisible by 3
Since H is a digit,
the possible values of H are: 2, 5 and 8Since we can’t answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: N is divisible by 5.Key property: If a number is divisible by 5, then its units digit must be either 0 or 5the possible values of H are: 0 and 5 Since we can’t answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined Statement 1 tells us that
the possible values of H are: 2, 5 and 8Statement 2 tells us that
the possible values of H are: 0 and 5 Then statements 1 and 2 are both true, it must be the case that
H = 5, since that's the only value that satisfies both statements.
Since we can now answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C
Cheers,
Brent