You and your friend sam are going to paint your 300 square feet room together. sam takes 10 minutes to paint 25 square feet. you take 5 minutes to paint 25 square feet. sam says, "if we paint together, then it will take us 15 minutes to paint 50 square feet! '' write a exceptional explanation to convince sam that he is wrong. you.

Fraction that Sam painted in 1 min is:
10/25=2/5
Fraction that you painted in 1 min:
5/25=1/5

Fraction pained by both in 1 min:
1/5+2/5=3/5 ft²/min
Time taken to paint 50 ft² will be:
time=3/5×50=30 min
Thus we conclude that Sam was wrong.

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!