Question

A bag contains counters that are red, black , or green . 1/3 of the counters are red 1/6 of the counters are black There are 15 green counters in the bag. How many black counters are in the bag ?

Answer 1

There are 5 black counters in the bag.

Explanation:

15 green counters in the bag

The proportion of green counters is given by:

`p = 1 - ((1)/(3) + (1)/(6)) = 1 - ((2)/(6)+(1)/(6)) = 1 - (3)/(6) = 1 - (1)/(2) = (2)/(2) - (1)/(2) = (1)/(2)`

So, we have that, the total is x. So

`(x)/(2) = 15`

`x = 30`

There are 30 total counters.

How many black counters are in the bag ?

A sixth of the counters are black. So

`(1)/(6) * 30 = (30)/(6) = 5`

There are 5 black counters in the bag.