Question

One red, two blue, and three green balls together weigh 20 pounds. Two red, four blue, and seven green balls together weigh 50 pounds. What is the weight of the green balls?

• A. 8 pounds
• B. 12 pounds
• C. 9 pounds
• D. 10 pounds

Answer 1

The correct option is D 10 pounds

Let the weight of red ball = x
Weight of the blue ball = y
Weight of the green ball = z

According to the given conditions, we can form two equations.

x + 2y + 3z = 20 .......eq 1
2x + 4y + 7z = 50 .....eq 2

Let's solve equation 2.
2x + 4y + 7z = 50
2x + 4y + 6z + z = 50
2(x + 2y + 3z) + z = 50

Substituting the value of x + 2y + 3z, we get:

$2\times 20+z=50$
40 + z = 50
z = 50 – 40 = 10 pounds

So, the weight of the green ball is 10 pounds.