# Puzzle problem

#### GreenMile

Hi there!

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

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

Thank you.

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

x=multiplication

#### Jhevon

Hi there!

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

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

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

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