A coin collector decides to divide his coin collection between his children.
The eldest gets 1⁄2 of the collection, the next gets 1⁄4 of the collection, the next gets 1⁄5 of the collection, and the youngest gets the remaining 49 coins.
How many coins are in the collection?
Puzzle Copyright © Kevin Stone
workings hint hide answer print
Answer
There are 980 coins in the collection.
Reasoning
Using fractions:
1⁄2 + 1⁄4 + 1⁄5 = 19⁄20
The remaining 1⁄20 is 49 coins.
Therefore, the 20⁄20 must equal 20 lots of 49 = 980.
Alternative Reasoning
Using percentages:
50% + 25% + 20% = 95%
The remaining 5% is 49 coins.
If 5% is 49 coins, 10% is 98 coins, 100% is 980 coins.
Double-Checking
1⁄2 of 980 is 490
1⁄4 of 980 is 245
1⁄5 of 980 is 196
and the remaining 49 coins.
And 490 + 245 + 196 + 49 = 980.