Question

The 10th term of an AP is -4 and it's 22nd is -16. Find it's 38th term?

Answer 1

AP10= -4

AP22= -16

AP 38= ??

AP10= -4

a+(10-1)d=-4

a+9d= -4 .................. (i)

similarly,

Ap22= -16

a+(22-1)d= -16

a+22d= -16.................. (ii)

Now from equation (i) &(ii)

we get, d= -12/13

putting d= -12/13 in equation (i)

a+9 (-12/13)=-4

a-108/13=-4

a= -4+108/13

a=56/13

ap38= a+ 37d

= 56/13+37 (-12/13)

= -388 ANSWER