All Exams Test series for 1 year @ ₹349 only
Question

If 9A7B is divisible by 55, find A + B.

The correct answer is
5

To solve the problem of finding the sum A + B where the number \(9A7B\) is divisible by 55, we need to understand the divisibility rule for 55. A number is divisible by 55 if it is divisible by both 5 and 11.

Divisibility by 5: A number is divisible by 5 if its last digit is 0 or 5. Therefore, \(B\) should be 0 or 5. Let's consider \(B = 5\) as this satisfies divisibility by 5.

Divisibility by 11: A number is divisible by 11 if the difference between the sum of its digits at odd positions and the sum of its digits at even positions is a multiple of 11.

For the number 9A7B:

  • Odd-positioned digits: 9 and 7
  • Even-positioned digits: A and 5

To satisfy the equation, we need:

\(11 - A = 0 \Rightarrow A = 11\)

However, \(A\) must be a singular digit. Adjust \(B\) so \(11 - A = \text{multiple of } 11\), such that it keeps within a valid digit scope.

Using \(B = 5\) previously determined:

For \(A = 0\), the expression becomes: \(16 - (0 + 5) = 11\), satisfying the divisibility rule for 11.\)

Thus, \(A = 0\) and \(B = 5\).

Therefore, \(A + B = 0 + 5 = 5\).

Conclusion: The sum A + B is \(5\).

Was this answer helpful?

Important Questions from Divisibility and Remainder

  1. If all positive divisors of 132 are arranged in descending order, then what digit will be at unit place of first divisor ?

  2. If 3 2019 is divided by 10, then what is the remainder?

  3. The number 3798125P369 is divisible by 7. What is the value of the digit P?

  4. Consider all 3-digit numbers (without repetition of digits) obtained using three non-zero digits which are multiples of 3. Let S be their sum.

    Which of the following is/are correct?

    1. S is always divisible by 74.

    2. S is always divisible by 9.

    select the correct answer using the code given below:

  5. How many 3-digit natural numbers (without repetition of digits) are there such that each digit is odd and the number is divisible by 5?

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App