The easiest way to do this would be to imagine that Jolie has 100 marbles. If Mary has 40% fewer, that means she has 60 marbles. Then if they combine all their marbles into a single bag, they will have 160 marbles, of which 100 are Jolie's. So the % that is Jolie's is 100/160 = 0.625 = 62.5%.
A circular pool with a diameter of 18 ft will have a uniform
4 ft concrete walkway poured around it. If the concrete cost $4.25 a square
foot, how much will it cost for the concrete?
This can be solve be solving the area of walkway
Area of walkway is equal to = (pi)( 9 ft +4) ^2– (pi)(9ft)^2
= 276.46 sq ft
Cost = 276.46 sq ft * ($4.25 a square foot) = $1174.70
