(a)[2]
Sara has a bag with 60 red counters, 72 blue counters and 36 green counters. Find the ratio of red counters : blue counters : green counters in the bag. Write the ratio in its simplest form.
(b)[3]
Sunil has a bag containing yellow counters and white counters. The ratio of yellow counters to white counters is $5:8$. There are 18 more white counters than yellow counters. Work out the number of yellow counters and the number of white counters.