The ratio of the number of dogs to cats to birds in a pet shop is 9:6:10. The number of dogs and cats is 45 altogether. If 10 dogs, 7 cats and 8 birds were sold, how many of the three kinds of pets remain?
Dogs:
Cats:
Birds:
Set the number of dogs as 9 units, cats as 6 units and birds as 10 units. So, the sum of dogs and cats is (9 + 6 = 15) units. Then,
15 units = 45
1 unit = 45 ÷ 15 = 3
9 units = 9 × 3 = 27
6 units = 6 × 3 = 18
10 units = 10 × 3 = 30
Thus, the remaining number of pets of each kind:
Dogs: 27 - 10 = 17
Cats: 18 – 7 = 11
Birds: 30 – 8 = 22