Here 345 represents the total area (in sq ft) shoveled; x repres. Melinda's rate and y represents Paul's rate. We need to solve for x and y and then subtract the smaller from the larger.
</span>30x + 30y = 450 Multiply this eqn by 2: 6<span>0x + 60y = 900 </span>20x + 25y = 345 Mult this eqn by -3: -60x -75y = -1035 --------------------------- -15y = -135 y = 9
This comes to 9 square feet per minute. Now, let's find x: 30x + 30y = 450; 30x + 270 = 450; 30x = 180; x = 6
Melinda can shovel 6 sq ft in 1 min, whereas Paul can shovel 9.
The difference is (9 - 6) sq ft / min, or 3 sq ft / min (answer)
