Answer: Hello mate!
we have the system of equations
30x + 30y = 450
20x + 25y = 345
where x is the number of square feet of snow that Melinda shovels in one minute, and y is the number of square feet of snow that Paul shovels in one minute.
Let's solve the system of equations, first, isolate one of the therms in the first equation, for example, x.
30x+30y = 450
x + y = 450/30 = 15
x = 15 - y
now we can replace it in the second equation and solve it for y.
20x + 25y = 345
20(15 - y) + 25y = 345
300 - 20y + 25y = 345
5y = 45
y = 45/5 = 9
Paul can shovel 9 square feets of snow in one minute, now replace it in the first equation and solve it for x.
x + y = 450/30 = 15
x + 9 = 15
x = 15 - 9 = 6
so melinda sholves 6 square feet of snow in one minute.
The question is:
How much more can Paul shovel in 1 minute than Melinda?
We need to see the difference y - x = 9 - 6 = 3
this means that paul shovels 3 more square feet per minute than Melinda.