Question

Bobby has a bag containing 2 sizes of marbles. The big ones weigh 10 g and the small ones weigh 3 g. If there are three times as many small ones as big ones and the bag weighs 209 g, how many big marbles does he have?

Answer 1

There are 19 big marbles

Explanation:

10a + 3b = 209

a = 3b

3b = 3b

10a + a = 209

11a = 209

a = 209/11

a = 19