Me with this problem and explain : )

The price of one more-expensive blouse) . . . . .  P
The cost for three of them . . . . . . . . . . . . . . . .  3 P

The price of one less-expensive blouse . . . . .  P - 3
The cost for three of them . . . . . . . . . . . . . .  3(P-3)  =  3P - 9

The cost for all six blouses . . . . .      3P  +  (3P - 9)

That's  $91.50 .                               3P  +  (3P - 9)  =  $91.50

                                                     3P  +   3P - 9   =  $91.50

Combine like terms:                        6P   -  9  =  $91.50

Add  9  to each side:                      6P          =   $100.50

Divide each side by  6 :                   P          =     $16.75

Each more-expensive blouse cost  $16.75 .

Each less-expensive blouse cost  $13.75 .

Check:         3 ($16.75)  +  3 ($13.75)

                =     $50.25     +     $41.25   

               =                 $91.50                         yay !