The sum of the first terms of an arithmetic progression is and its -th term is

MATHEMATICS · Subjective · A Level · Mathematics · Sequences and series · Sequences and series

Problem

The sum of the first

n

terms of an arithmetic progression is

175

and its

n

-th term is

31

. The first term of the progression is

4

. (i) Form two algebraic equations involving

n

and the common difference

d

from the above information. (ii) Solve the equations simultaneously to find the values of

n

and

d