Q41 of 84 Page 5

Find the sum of the first 40 positive integers divisible by 6. ? (CBSE 2012)

The smallest positive integer which is divisible by 6 is 6 itself and its 40th multiple will be 6 x 40 = 240

So, we have a = 6, d = 6, n = 40 and 40th term = 240.

Sum of first 40 positive integers divisible by 6 can be calculated as follows:

= 20(12 + 234)

= 20*246

= 4920

The 17th term of AP is 5 more than twice its 8th term. If the 11th term of the AP is 43, find its nth term? (CBSE 2012)

If 4 times the 4th term of an AP is equal to 18 times its 18th term then find its 22nd term? (CBSE 2012)

The nth term of an AP is given by (- 4n + 15). Find the sum of first 20 terms of this AP? (CBSE 2013)