Find the two-digit numbers A and B such that the number 65AB0 is divisible by…
2025
Find the two-digit numbers A and B such that the number 65AB0 is divisible by 66.
- A.
15, 16
- B.
16, 16
- C.
17, 17
- D.
17, 18
Attempted by 5 students.
Show answer & explanation
Correct answer: C
Step-by-Step Solution
Analyze the Divisor: To be divisible by 66, a number must be divisible by its co-prime factors, which are 2, 3, and 11.
Apply Divisibility Rules:
Divisibility by 2: The number 65AB0 ends in 0, so it is even and satisfies the rule for 2.
Divisibility by 3: The sum of the digits must be divisible by 3.
Divisibility by 11: The alternating sum of the digits must be divisible by 11.
Test Option C (A=17, B=17): The number becomes 6517170.
Sum of digits: 6 + 5 + 1 + 7 + 1 + 7 + 0 = 27. Since 27 is divisible by 3, the number satisfies the divisibility rule for 3.
Alternating sum: (6 + 1 + 1 + 0) - (5 + 7 + 7) = 8 - 19 = -11. Since -11 is divisible by 11, the number satisfies the divisibility rule for 11.