# Math Help - Puzzle problem

1. ## Puzzle problem

Hi there!

$6*7=30$
$7*5=24$
$4*9=24$
$8*5=?$

According to the first three relations find $8*5=?$.

Thank you.

2. (6-1)x(7-1)=30
(7-1)x(5-1)=24
(4-1)x(9-1)=24

x=multiplication

3. Originally Posted by GreenMile
Hi there!

$6*7=30$
$7*5=24$
$4*9=24$
$8*5=?$

According to the first three relations find $8*5=?$.

Thank you.
here is the relation: $a*b = (a - 1)(b - 1)$

EDIT: well geez, thanks a lot Adarsh. I left the problem unanswered so long, but you decided to answer right before i did