A farmer counts 30 animal heads and 86 animal legs across a pasture filled entirely with ducks and cows. How many cows are in the pasture?
13 cows
If all 30 animals were ducks, there would be 60 legs. The extra 26 legs belong to cows (2 extra per cow), so 26 / 2 = 13 cows (and 17 ducks).
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
More math riddles
I am a two-digit prime number. If you reverse my digits, the new number is also prime, and the difference between us is 18. What number am I?
I am a closed geometric shape with four straight sides of equal length, but none of my interior angles measure 90 degrees. What specific shape am I?
One sparkler costs 5 dollars. How many dollars do 6 sparklers cost?
I start with a single bacterium. Every minute, each bacterium splits into two. If the jar is completely full in 60 minutes, at what minute was the jar exactly half full?
A box contains a collection of marbles. If you count them by twos, you have one left over. If you count them by threes, you have two left over. If you count them by fours, you have three left over. What is the smallest possible number of marbles in the box?
Zoe puts 3 eggs in each of 5 boxes. How many eggs is that altogether?