Question

Elena is knitting a design on a sweater. The first row has 10 stitches and each

additional row has 7 stitches more than the row before it. How many stitches are in
the 12th row?
A.74
B.70
C.87
S.86

Answer 1

Answer: 87

Explanation:

This will be solved using an arithmetic progression. The formula will be:

= a + (n - 1)d

where,

a = first term = 10

d = common difference = 7

n = 12

Therefore, 12 term will be:

= a + (n - 1)d

= 10 + (12 - 1) × 7

= 10 + (11 × 7)

= 10 + 77

= 87

Therefore, the number of stitches that are in the 12th row will be 87.