Question

Find the
sum
of all multiples of 9 lying between 300 and 700​

Answer 1

Answer:

The multiples of 9 lying between 300 and 700 is 21,978.

Step-by-step explanation:

A.P. formed is 306, 315, 324, .......... , 693

Here first term = a = 306, common difference = d = 9 and last term = l = 693

693 = 306 + (n - 1)9

77 = 34 + n - 1

n = 44

Sum = n/2(a + l)

= 22(306 + 693)

= 21978