Question

A sum of 5



a.p is 30 and there square is 220. find the third no

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.