Question

Find the 31 st term of an AP whose 11th term is 38 and 16 th term is 73

Answer 1

given : 11 th term = 38
16 th term = 16

therefore,
a+10d = 38......(1).from formula añ= a+(n-1)d
a+15d = 73.......(2)

sub eqn. 1 from 2

5d = 35
d = 7
put d = 7 in eqn 1...

a = - 32

therefore,
31 st term = a + 30 d

put the values of a and d

=> -32+ 7 = - 25

31 st term will be -25 ...


hope it will help you....