Q11 of 202 Page 9

Find the sum of all natural numbers between a and 100, which are divisible by 3.

a = 3, l = 99, n = 33

S₃₃= (a + l)

= (3 + 99)

= (102)

= 33 (51) = 1683

If 12^th term of an A.P. is 13 and the sum of the first four terms is 24, what is the sum of first 10 terms?

Find the sum of first 22 terms of an A.P. in which d = 22 and a₂₂ = 149.

Find the sum of first n odd natural numbers.

Find the sum of all odd numbers between

(i) 0 and 50

(ii) 100 and 200