The 5th term of an arithmetic sequence is 38 and the 9th term is 66. What its 10th term is
73
x5=28&x9=66
⇒x1+4d=38 & x1+8d=66
Solving
x1+4d=38 x1+8d=66 − − − ––––––––––––––– −4d=−28 d=7
∴x1+4(7)=38
x1=38−28
x1=10
∴ 10th term =x10=x1+9d
=10+9(7)
=10+63
=73