A father is 4 times as old as his daughter. In 20 years, he will be twice as old as her. How old is the daughter today?
10 years old
Let daughter be x, father 4x. In 20 years: 4x + 20 = 2(x + 20). 4x + 20 = 2x + 40, so 2x = 20, x = 10.
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: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
More math riddles
Ben counts fireworks in a pattern: 2, 6, 10, 14. How many fireworks come next?
There are 12 snowballs in a box and 5 are taken out. How many snowballs are left?
Find a four-digit number where the first digit is one-third of the second, the third digit is the sum of the first and second, and the fourth digit is three times the second.
I am a two-digit multiple of 7. If you add my digits together, the sum is a prime number. What number am I?
Eli makes 2 rows of 3 carrots and adds 3 more at the end. How many carrots are there in all?
A buyer purchases ducks for $4 each and geese for $7 each, spending precisely $53. If the buyer obtained more ducks than geese and bought at least one of each, what was the total number of birds purchased?