Find the sum of all integers between 100 and 550, which are multiples of 9.

Find the sum of all integers between 50 and 500, which are multiples of 7.

Find the sum of all even integers between 101 and 999.

In an A.P. if the first term is 22, the common difference is – 4 and the sum to n terms is 64, find n.

In an A.P. If the 5^th and 12^th terms are 30 and 65 respectively, what is the sum of first 20 terms?