Question

The sum of 5 numbers in ap is 30 and the sum of their squares is 220. which of the following is the third term?

Answer 1

Let five numbers in A.P. be a – 2d, a – d, a, a + d and a + 2d.
Given (a – 2d) + (a – d) + a + (a + d) + (a+ 2d) = 30
Putting a = 6, we get
When a = 6 and d = 2, we get
when a = 6 and d = –2, we get
Five numbers in A.P. are 2, 4, 6, 8 and 10.
Thus, the third number is 6.

Answer 2

Answer:

6

Step-by-step explanation:

In an AP with 5 terms, the 3rd term will always be the average. Since we know the sum is 30 and there are 5 terms, We can figure out that the average is

30/5 = 6

Hence the 3rd term has to be 6

This can also be done by assuming variable but using logic like this will save you a lot of time.