Question

Andy has some counters.

15% of the counters are red.
2/5 of the counters are blue.
The rest of the counters are yellow.
There are 27 yellow counters.
How many blue counters are there?

Answer 1

24 blue counters

you must find what percent is shown by the yellow counters and then calculate the 1% to then multiply by the percent shown by the blue counters to give you the number of counters

15% = 15/100
2/5 = 40/100

15+40 = 55 --> 55/100
100 - 55 = 45

so 27 counters = 45/100

27 divided by 45 = 0.6 (= 1%)
0.6 x 40 = 24