Question

Devon has 14 steel balls of equal weight. If he puts 8 of them in one pan of a balance, and the rest along with a weight of 20 grams in the other pan, the pans balance each other. Which equation can be used to find the weight of each steel ball?

Answer 1

Let n be a number of balls: n = 14

In one pan you have 8 balls: 8n
In the other pan you have the rest of balls (14 - 8 = 6) along with a weight of 20 grams = 6n + 20
So the pans are balanced:
8n = 6n + 20

Now, just solve the equation:
8n - 6n = 20
2n = 20
n = 20/2
n = 10
So, you know that a ball weights 10 grams.

Answer 2

Answer:

Let x represent the weight of one steel ball. One side will have 8 balls or 8x and the other side will have 14-8 or 6 balls (6x) and the 20 gram weight. 8x = 6x + 20.