Question

Bobby has a bag containing 2 sizes of marbles. The big ones weigh 10 g and the small ones weigh 2 g. If there are five times as many small ones as big ones and the bag weighs 300 g, how many big marbles does he have?

Answer 1

He has 15 big marbles and 75 small ones.

Explanation:

If you plug in 15 you have 15x10+15x2x5=___. When you work it out you get 300.