15 & 16 plz solved. 10.
II.
14.
15.
16.
17.
18.
multiples of 5.
Find the sum of all integers between 200 and 400 which are divisible by 7.
If the sum to n terms of a sequence he n + 2n, then prove that the seqaence is
an A F.
(i) Find the sum to n terms Of an A.P. whose kth term is 5k + l.
(ii) Find the sum of all numbers of two digits which leaves the remainder 1
when divided by 4.
If the sum of n terms of an A.P. in 3n +5n and its mth term is 164, find the
value of m.
[Hint : = 3m 1) = 6m +2]
If the sum of n terms of an A.P. is pn+qn , where p and q are constants, find
the common difference.
f the sum •f n terms of an A.P. in l) e, where P and e are
constants, find the common difference of the A.P.
If the sum of 8 terms of an A.P. is 64 and the sum of 19 terms is 361, find the
sum of n terms.
[f a, b, c be the 1st, 3rd and nth terms respectively of an A.P., prove that the
2
2
sum to n terms is
2
and the nth term is — , then prove that
If the mth term of an A.P. is —
m
