Q13 of 49 Page 112

Find the sum of the first 15 multiples of 8

Given: a = 8, d = 8 and n = 15


Sum of first 15 multiples of 8 can be calculated as:




= 15(8 + 56)


= 15*64


= 960


More from this chapter

All 49 →
11

If the sum of the first n terms of an AP is what is the first term (that is S1)?

Whatis the sum of first two terms? What is the second term? Similarly, find the 3rd, the 10th andthe nth terms.

 12

Find the sum of the first 40 positive integers divisible by 6

 14

Find the sum of the odd numbers between 0 and 50

 15

A contract on construction job specifies a penalty for delay of completion beyond acertain date as follows: Rs 200 for the first day, Rs 250 for the second day, Rs 300 for the third day, etc., the penalty for each succeeding day being Rs 50 more than for thepreceding day. How much money the contractor has to pay as penalty, if he has delayedthe work by 30 days?