Question

The tenth term of an AP is 30 and the eleventh term is 50. Find the AP.

Answer 1

Answer:

Given: 6th term A6= 20, 11th term A11=30

we have, An= A1+(n-1)d

=> A6=A1+(6–1)d

=> 20=A1+5d ——equation (1)

A11=A1+(11–1)d

=> 30=A1+(11–1)d

=> 30= A1+10d ——equation (2)

equating 1 and 2, we have

=> d=2, substitute in eq(1)

=> 20= A1+5(2)

=>A1=20–10=10

Hence, the first term A1=10 and common difference d=2.

Step-by-step explanation: