Question

Dan is watching The Birds in his backyard. Of the birds he watches, 9. Of them,or 45%, are sparrows. How many birds are in his backyard?

Answer 1

If 9 of the sparrows is 45% of the birds in the backyard, 9/x = 45/100.

Cross multiply to get 9 * 100 = 45x; simplified is 900 = 45x or 20.

This means that there are 20 birds in the backyard. You can check this by dividing 9/20 which equals 45%