Question

Marco paints a wall and charges $20 as set up fee. He charges at least $60 per big wall and he for small walls he charges no more than $40 per wall.He has just completed painting either all big walls or small walls.
His invoice states that he received $2420 in payment.How many walls could he have painted?

I did like this, 20+60b<=2420
b<= 60 big walls
or 20+40s>=2420
s>=40 small walls.
so , atmost 60 big walls or atleast 40 small walls. Is this correct? Please help me.

Answer 1

at most 40 big walls
(less, if he charges more than $60 each)

at least 60 small walls
(more, if he charges less than $40 each)