Question

find five numbers in A.P. whose sum is 12
and the ratio of the first to the last terms is
2:3​

Answer 1

Step-by-step explanation:

Sum of an AP is give by

Sn=2n[2a+(n−1)d]

Since sum of first 5 terms is given so

S5=25[2a+(5−1)d]

225=25[2a+4d]

a+2d=25..(1)

Also given,

da=32

a=32d......(2)

Putting value of a from (2) to (1) we get

32d+2d=25

32d+6d=25

4d+12d=15

16d=15

d=1615

Putting value of d in (2)

a=32d=32