The 11th term of an arithmetic profression is 1. The sum of the first 10 terms is 120. Find the 4th term.
Hi Tesphen.
The sum of the first 11 terms is 121. Hence the 6th term in the series is (NB: The sum of an odd number of terms of an A.P. is the product of the middle term and the number of terms.) The common difference is therefore You should be able to find the 4th term from here.
Hello, Tesphen!
I must assume you know these formulas:
. . . . . . . . .
where: . = first term, = common difference.
The 11th term of an arithmetic profression is 1.
The sum of the first 10 terms is 120.
Find the 4th term.
The 11th term is 1: . .[1]
The sum of the first 10 terms is 120:
. . .[2]
Solve the system: .
. . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .