Question

Find 31st term of an A.P whose 11th term is 38 and the 16th term is 73

Answer 1

Answer:

Step-by-step explanation:

A.T.Q

a+10d=38.....(i)

a+15d=73......(ii)

Subtracting (ii) from (i)

-5d=-35

d=7

a=38-70

  =-32

31st term=a+30d

              =-32+210

              =178

Answer 2

Answer:

Step-by-step explanation:

Given:

11 term= 38 and

16 term=73

nth term = a +(n-1)d

=> a+(11-1)d = 38

or, a+10d=38 ...................................(i)

a+ (16-1)d =73

or, a+15d=73 ...................................(ii)

subtract (i) from (ii)

=> a+15d =73 -

- (a+ 10d =38)

..............................

=> 5d = 35

or d = 7

substitute value

a+10d =38

or a + 70 = 38

or, a = -32

31 terms

-32 + 30x7

=178