Problem 8 · 2025 Math Kangaroo
Medium
Arithmetic & Operations
work-backward
A dog has 2 puppies that both weigh the same. Picture 1 shows that the dog and one puppy together weigh 14 kilograms. Picture 2 shows that the dog and both puppies together weigh 18 kilograms. How many kilograms does the big dog weigh?
Show answer
Answer: B — 10
Show hints
Hint 1 of 3
The two pictures are the same except one has one more puppy.
Still stuck? Show hint 2 →
Hint 2 of 3
The extra weight from picture 1 to picture 2 is just one puppy.
Still stuck? Show hint 3 →
Hint 3 of 3
Once you know how heavy one puppy is, take it away from the 14 kg picture to find the dog.
Show solution
Approach: the extra puppy tells you one puppy's weight, then find the dog
- Picture 1 is the dog and one puppy (14 kg). Picture 2 is the dog and both puppies (18 kg).
- Going from 14 kg to 18 kg adds one more puppy, so one puppy weighs 4 kg.
- Take that puppy away from picture 1: 14 take away 4 leaves 10 kg for the dog. The answer is B.
Mark:
· log in to save