Question

The 5 the term of an AP is 38 and 9 th term is 66 what is the 25 the term ?

Answer 1

Answer:

use formula an = a + (n-1)d

Step-by-step explanation:

eq 1.) 38 = a + (5-1) d

eq2.) 66 = a + (9-1) d

solve both the equations by using any method of elimination or substitution and you will get the values of a and d and by which you can calculate 25th term

Answer 2

Answer:

5th term=a+4d

9th term=a+8d

now

a+4d=38 and a+8d=66

by eliminating these two equations a gets canceled and d becomes -4d and 38-66= -28

so, -4d= -28

d = -28÷ -4 = 7

so, d=7

substitute d=7 in a+4d = 38

a+4×7 = 38

a+28=38

a=38-28

a=10

so, a=10 and d=7

25th term = a+24d

10+24×7

=10+168

a25=168

therefore 25th term is 178