Question

The first term of an A.P. is 4 and
the last is 20. The sum of the terms
252. Calculate the number of
terms and the common difference
of the A.P​

Answer 1

Answer:

n = 21, d = 3/4

Step-by-step explanation:

Given:

a = 4

an = 20

Sn = 252

Formula used :- Sn = n/2(a +an)

252 = n/2( 4 + 20)

504 = n(24)

21 = n

We know, an = a + (n-1)d

Putting values :-

20 = 4 + (21-1)d

15 = (20)d

3/4 = d