# How do I solve this multiplication problem?

I am trying to answer this puzzle my friend created and sent to me - which of the five potential answers is correct, and why?

$$10 \times 5 = 60 \\ 6 \times 12 = 72 \\ 8 \times 3 = 44 \\ 5 \times 9 =\,?$$

Possible answers:

A) 54
B) 56
C) 58
D) 60
E) 62

• Hi! You need to include a source if you post a puzzle you didn't create. Also note that you can't include a question that is part of an ongoing competition. Thanks and happy puzzling! – Voldemort's Wrath Nov 8 '19 at 22:52
• My friend created this puzzle ant sent to me. – black Nov 8 '19 at 23:00
• I added the above information into the original post. I hope that helps, and welcome to PSE! – HTM Nov 8 '19 at 23:03

## 1 Answer

B)56

because:

if "a*b=c" then c=4(a+b)