Question 286007

Find the 15th term and the sum of the first 15 terms for the following sequences.
a) 12, 17, 22, ….
b) 4, 10, 16, ….
.
The formula is:
nth term = a + [(n - 1) * d]
where
a is the first term
n is the nth term
d is the distance
.
a) 12, 17, 22, ….
d is 5
n is 15
15th term = 15+[(15-1)*5] = 15+[14*5] = 15+[70] = 85
b) 4, 10, 16, ….
d is 6
n is 15
15th term = 4+[(15-1)*6] = 4+[14*6] = 4+[84] = 88