Proportional relationships

Question

Tomas collects sport cards. The number of baseball cards he buys each week is proportional to the number of football cards he buys. Fill in the missing numbers

week 1 2. 3. 4.

baseball card: 9. 15. 6

# of football cards 6. 8.

suppose Tomas buys a total of 30 baseball and football cards in week 5 how many of each would he have to buy to keep the same proportional relationship

Answer 1

It looks like your number sets are

W 1, 2, 3, 4

B 9,15,u, 6

F 6, u, 8, u

I used u for unknown.

Ratio is B:F. Week 1 has the ratio 9:6 or if divided by 3, 3:2.

This can be written as 3/2. Week 2 has an unknown for the Football value so the proportional equation 3/2 = 15/u can be used to solve for u by cross multiplying to get 3u = 30 then dividing by 3. In this case, u is 10.

Using the same format, the u’s for weeks 3 and 4 can be found. 3/2 = u/8 and 3/2 = 6/u

The resulting table will be

W 1, 2, 3, 4

B 9,15,12, 6

F 6,10, 8, 4