Question

9. If the 4th term of an arithmetic progression is 12, and the sum of the first 10 terms is 60, what is
the difference between the 3rd and the 5th term?

a.8
b.16
c.12
d.4​

Answer 1

Answer:

8

Step-by-step explanation:

4th term is 12 so,

a+3d =12----1

and sum of first 10terms is 60

so 5 ( 2a +9d) =60

10a +45d=60

now by equation 1( multiply with 10)

10a + 30d =120

10a + 45d =60

d= -4

so,

a= 24

now

3rd term is,

a+2d that is

24-8=16

5th term is,

a+ 4d

24-16 =8

so difference between 3rd and 5th term is 8