Please help! due in 1 hour!! A trucker hauls citrus fruit from Florida to Montreal. Each crate of oranges is 4 ft3 in volume and weighs 60 lb. Each crate of grapefruit has a volume of 6 ft3 and weighs 75 lb. His truck has a maximum capacity of 300 ft3 and can carry no more than 4200 lb. Moreover, he is not permitted to carry more crates of grapefruit than crates of oranges. If his profit is $2.50 on each crate of oranges and $4 on each crate of grapefruit, how many crates of each fruit should he carry for maximum profit?

Ok here we go ..there are plenty of ways to solve such math problems but we will go for the smartest and easiest ..5x+2y=7  -2x+6y=9we rearrange them into the following ..by multiplying the 1st equation by 2 it becomes 10x + 4y = 14we rearrange it and so it becomes 10x = 14 - 4yas for the second equation we multiply it by 5 and rearrange it so it becomes as to the following ..-10x + 30y = 45rearranging so 10x = 30y -45now 10x equals both 14 - 4y and 30y -45so   14 - 4y = 30y -4531 = 26yy= 31/26 = 1.19 or around 1.2so by now we can calculate x easily as  -2x+6y=9so 2x = 6y -9 = 6 * 31/26 - 9 = -1.84  then x = - 0.92 or around -0.9best luck!