Question

26. Find the values of a, band c such that the
numbers a, 10, b, c, 31 are in AP.
[CBSE 2012]​

Answer 1

In this case

a,10,b,c,31 are in AP

in this AP the second term is 10 and

fifth term is 31

So,

where d is the common difference

a+d=10 first equation

a+4d=31 second equation

subtracting first equation from second we get,

3d=21

d=7

putting value of d in first equation we get

a=3

as the common difference is 7

So,

b=17

c=24

hope it helps

:-)