🦘 Math Kangaroo Grade All Felix 1-2 Ecolier 3-4 Benjamin 5-6 Kadett 7-8 Junior 9-10 Student 11-12 ⇄ switch contest
2016 Math Kangaroo

Problem 2

Problem 2 · 2016 Math Kangaroo Easy
Arithmetic & Operations careful-counting

In a cave there live a starfish, two seahorses and three turtles. They are visited by three starfish, four turtles and five seahorses. How many animals are there now in the cave altogether?

Show answer
Answer: E — 18
Show hints
Hint 1 of 2
Add up everyone who is now inside the cave: the original animals plus the visitors.
Still stuck? Show hint 2 →
Hint 2 of 2
Total the residents (1 + 2 + 3) and the visitors (3 + 4 + 5) separately, then combine.
Show solution
Approach: add residents and visitors
  1. Living there: 1 starfish + 2 seahorses + 3 turtles = 6 animals.
  2. Visitors: 3 starfish + 4 turtles + 5 seahorses = 12 animals.
  3. Altogether 6 + 12 = 18 animals.
Mark: · log in to save