Question

6.If 18y71 is divisible by 3, where y is a digit, then find the value of y.​

Answer 1

Answer:

y = 1

Test of divisibility of 3 is;

Sum of the digits must divide by 3 that means must give remainder as 0.

1+8+y+7+1 = must be a multiple of 3

or the number thus obtained must be divisible by 3 on adding it's digits that is 17+y must be divisible by 3 or 1+7+y = 8+y must be divisible by 3.

as y can't be a single digit number hence there's only one number that is 1 which by adding with 8 you'll get 9 that will be divisible by 3.

hence 1 is the answer.