Grade 4 word problems

Question

A rottweiler weighs five times as much as a Scottish terrier. The Scottish terrier weighs 36 kg less than the rottweiler. How much does each dog weigh?

Answer 1

Let's let the variable r represent the weight of the rottweiler and the variable s represent the weight of the Scottish terrier.

Since the rottweiler weighs 5 times as much as the terrier, we can write:

r = 5s

Also since the terrier weighs 36 grams less than the rottweiler, we can write:

s + 36 = r

We can substitute 5s for r in the second equation and solve for s:

s + 36 = r

s + 36 = 5s

s + 36 - s = 5s -s

36 = 4s

36/4 =4s/4

9 = s

So the Scottish terrier weighs 9 kg.

The rottweiler will weigh 5s or 5 * 9 = 45 kg