Mikes pet shop: add the ratio: 7+ 3 = 10
Divide total animals by the sum:
300/10 = 30
The ratio of cats is 7
Total cats = 30 x 7 =210
Do the same for Pets R Us:
Ratio: 6 + 4 = 10
150/10 = 15
Cats = 15 x 6 = 90
Total cats = 210 + 90 =300
Total animals = 300 + 150 = 450
Fraction that are cats = 300/450 = 2/3
2/3 of the animals are cats