**CBSE NCERT Solutions Chapter 5 Arithmetic Progressions Exercise 5.2 Question 18**

**18. The sum of the 4th and 8th terms of an AP is 24 and the sum of 6th and 10th terms is 44. Find the three terms of the AP.**

**Solution:**

The sum of 4th and 8th terms of an AP is 24 and sum of 6th and 10th terms is 44.

It means and

**Using formula** , to find nth term of arithmetic progression, **we can say that**

And,

And,

And,

And,

**These are equations in two variables. Lets solve them using method of substitution.**

Using equation , we can say that ** (1)**

Putting **(1)** in equation , we can say that

Putting value of in equation , we get

Therefore, first term

And, Common difference

**Therefore, AP is -13, -8, -3, 2, ....**

**Its first three terms are -13, -8 and -3.**