The number who needs to be separated into a ratio = 72
Total number of parts = 3 + 4 + 5
= 12 parts
Each part = 72 ÷ 12
= 6
Then 3 parts = 3 × 6 = 18
4 parts = 4 × 6 = 24
5 parts = 5 × 6 = 30
Then , the ratio will be , 18 : 24 : 30
Therefore , 72 in the ratio 3:4:5 will be = 18 : 24 : 30 .
