Question

Rodrigo and his cousin have 8 bags of marbles. Some of the bags contain 5 white marbles. The rest of the bags contain 7 pink marbles. They have 48 marbles in all. How many bags of each color marble do the cousins have?

Answer 1

The cousins have 4 bags of white marbles and 4 bags of pink marbles.

Explanation:

If x is the number of bags with white marbles and y is the number of bags with pink marbles, we can write the following system:

x + y = 8 -- Equation 1

5x + 7y = 48 -- Equation 2

5x + 5y = 40 -- Equation 3 (Multiply Equation 1 by 5)

2y = 8 -- (Subtract Equation 3 from 2)

y = 4 -- (Divide both sides by 2)

x + 4 = 8 -- (Substitute y = 4 into Equation 1)

x = 4 -- (Subtract 4 from both sides)