Ratios 7th grade

Question

if you need 3 1/3 cups of red paint and 1 1/3 cups of blue to make purple.

for every 1 cup of blue how many cups of red is needed.

For every 1cup of red how many blue?

for every 4 cups of red how many blue are needed?

Answer 1

r : b :: 3 1/3 : 1 1/3 statement of proportion

r : 1 :: 3 1/3 : 1 1/3 substitution of blue amount

3 1/3 = (1 1/3)(r) product means/extremes

10/3 = 4r / 3

10 = 4r

2.5 = r