Question

the sum of 3rd and 6th term in an ap is 24 and the sum of 11th and 12th term is 52, then what is the first term and the common difference?​

Answer 1

Step-by-step explanation:

Tn=a+(n−1)d

T4+T8=24

a+3d+a+7d=24

a+5d=12...(1)

T6+T10=34

a+5d+a+9d=34

a+7d=17...(2)

(2)-(1) gives:

∴d=25

From (1)

a=17−7d

a=17−7(25)

∴a=−21