The common difference of the arithmetic progression is: 8.75
What is the nth term of the arithmetic progression?
The formula for the nth term of an arithmetic progression is:
aₙ = a + (n - 1)d
where:
a is first term
d is common difference
Using the formula for the sum of an arithmetic progression, we have:
Sₙ = (a + aₙ)n/2
Thus:
380 = (7 + 77)n/2
n = 760/84
n ≈ 9
Thus:
77 = 7 + (9 - 1)d
d = 70/8
d = 8.75