Answer:
13
Step-by-step explanation:
The term is in an arithmetic progression.
That means there is 6 between each term and the next one.
Givens
a = -30
d = 6
last term an = 42
Formula
L = a + (n - 1)*d
Solution
42 = -30 + (n -1 )*6 Add 30 to both sides
42+30 = (n - 1) * 6 Combine the terms on the left.
72 = (n - 1)*6 Divide both sides by 6
72/6 = n - 1
12 = n - 1 Add 1 to both sides
12 + 1 = n
n = 13
