Q8 of 52 Page 1

How many two-digit numbers are divisible by 31?

Two digit Numbers which are divisible by 3 are 12, 15, 18 ...............,99.
Here;


a = 12 and


Common difference = 15 – 12 = 3


an = 99
nth term (tn) = a + ( n - 1) d
⇒ 99 = 12 + ( n - 1) 3
⇒ (n - 1)3 = 99 - 12 = 87
⇒ (n -1) = 87/3
⇒ n - 1 = 29
n = 30
There are 30 such numbers.


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