Question

For his science fair project, Bryan is comparing slime recipes. For one batch, he weighs out 9
3
4
ounces of liquid starch and mixes it with 2 bottles of glue. For the other batch, he weighs out 7
3
4
ounces of liquid starch and mixes it with 2
1
2
bottles of glue. Both batches end up weighing the same amount.
Which equation can you use to find w, the weight of a bottle of glue in ounces?
How much does a bottle of glue weigh?
Simplify any fractions.

Answer 1

Let w = weight of one bottle of glue in ounces. The equation is

9 3/4 + 2w = 7 3/4 + 2 1/2 w.

Convert to fractions or solve directly:
(9 3/4) − (7 3/4) + 2w = (2 1/2)w
2 + 2w = (5/2)w
2 = (5/2)w − 2w = (1/2)w
w = 2 ÷ (1/2) = 4.

A bottle of glue weighs 4 ounces.