The first term is a1=7 and the 6th term is a6=22.
The general term of an arithmetic progression is:
an=a1+(n−1)×d
For the 6th term:
a6=a1+(6−1)×d
22=7+5d
15=5d
d=3
The sum of the first n terms of an arithmetic progression is:
Sn=2n×[2a1+(n−1)×d]
For the first 10 terms with a1=7 and d=3:
S10=210×[2(7)+(10−1)×3]
S10=5×[14+9×3]
S10=5×[14+27]
S10=5×41
S10=205
Therefore, the sum of the first 10 terms is 205.