Question

If 5 # 3 = 19 and 7 # 2 = 17, what is 9 # 1?

• A. 12
• B. 10
• C. 8
• D. 11

Answer 1

Answer:

D. 11

A simpler pattern fits the given examples:

• $(5 \# 3 = 5 \times 3 + 4 = 19)$

• $(7 \# 2 = 7 \times 2 + 3 = 17)$

The added number decreases by 1 each time:

• (+4, +3,) so next is (+2)

Therefore,

$9 \# 1 = 9 \times 1 + 2 = 11$

So the answer is 11.