Question

find the sum of all two digit no. whose sum of digits is divisible by 7 and the no. is divisible by 3​

Answer 1

Answer:

The two digit number which gives a remainder of 3 when divided by 7 are:

10, 17, 24 ..... 94.

Now, these number are in AP series with

1st Term, a = 10;

Number of Terms, n = 13;

Last term, L = 94 and

Common Difference, d = 7.

Sum,

= {n*(a+L)/2}

= 13*52 = 676.