Ashopper bought three of the same shirt and paid $63 and after the 30 percent discount. what was the original price of one of the shirts

X=the original price of one of the shirts
we have this equation:
3(x - 30x/100)=63
We solve this equation
3x-  90x/100=63
300x-90x=6300
210 x=6300
x=6300/210=30

The original price of one of the shirts was $30.

to check
the cost of 3 shirt was= 3 *$30=$90.
if we do the 30 percent discount=$90-30% of $90=$90-(30/100)*$90=
=$90-(30*$90)/100=$90-$27=$63.

The slope of the function is 0.5.