Question

Write a digit in the blank space of each of the following numbers so that the number formed is divisible by 11:

1) 92 __ 389

2) 8 __ 9484

Answer 1

(a) We know that a number is divisible by 11 if the difference of the sum of the digits at odd places and that of even places should be either 0 or 11.
Therefore,
928389 → Odd places = 9 + 8 + 8 = 25
→ Even places = 2 + 3 + 9 = 14
→ Difference = 25 – 14 = 11

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(b) We know that a number is divisible by 11 if the difference of the sum of the digits at odd places and that of even places should be either 0 or 11.
Therefore,
869484 → Odd places = 8 + 9 + 8 = 25
Even places = 6 + 4 + 4 = 14
Difference = 25 – 14 = 11