Question

How many quarts of water must be added to 4 quarts of an 80% mixture to obtain a 50% mixture?

Answer 1

Volume of water in the 4 quarts = 20% x 4 = 0.8 quarts

Let the volume of water to be added = x quarts


Total volume = (x + 4) quarts

This volume contains 50% water

so;

(0.8 + x)/(x + 4) x 100 = 50

(0.8 + x)/(x + 4) = 0.5


0.8 + x = 0.5x + 2

x - 0.5x = 2 - 0.8

0.5x = 1.2

x = 2.4

2.4 quarts of water needs to be added

Answer 2

Answer:

Step-by-step explanation:

Volume of water in the 4 quarts = 20% x 4 = 0.8 quarts

Let the volume of water to be added = x quarts

Total volume = (x + 4) quarts

This volume contains 50% water

so;

(0.8 + x)/(x + 4) x 100 = 50

(0.8 + x)/(x + 4) = 0.5

0.8 + x = 0.5x + 2

x - 0.5x = 2 - 0.8

0.5x = 1.2

x = 2.4

2.4 quarts of water needs to be added