PLEASE HELP MATH 50pts + brainliest
Please explain

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

Mikes car gets an average of 28 mpg. there are 12 gallons of fuel in mikes car when he starts his trip of 140 miles. about how many gallons are left at the end of his trip?

Asoftball team played ten games, scoring 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 runs. they lost by one run in exactly five games. in each of their other games, they scored twice as many runs as their opponent. how many total runs did their opponents score?