A chemist has two solutions: a 50% methane solution and an 80% methane solution. He wants 100 mL of a 70% methane solution. How many of each solution does he need to mix? Write two expressions in a system of equations to show this problem.

Franco wants to double the volume of the cone. what should he do?

Find the number of liters in 12.8 gal of gasoline. round to the nearest hundredths

Pyotr tchaikovsky sporting goods operates on a 45% overhead based on the selling price, which results in an overhead of $65.34 on the newest version of an air hockey game set. if the air hockey game set costs pyotr tchaikovsky sports $49.32, find the selling price, the markup, and the net profit.