The sum of first 10 terms of the arithmetic progression is 74.5
What is the sum of first 10 terms of the arithmetic progression
From the question, we have the following parameters that can be used in our computation:
a6 = 7
a = 11.5
The nth term of an expression is represented as
a(n) = a + (n - 1)d
So, we have
11.5 + (6 - 1)d = 7
5d = -4.5
Evaluate
d = -0.9
So, we have
The sum of first 10 terms of the arithmetic progression is
Sn = n/2(2a + (n - 1) * d)
Substitute the known values into the equation
S(10) = 10/2 * (2 * 11.5 + (10 - 1) * -0.9)
Evaluate
S(10) = 74.5
Hence, the sum of first 10 terms of the arithmetic progression is 74.5