Random Puzzles 

Workings

Hint
What do the fractions add up to?

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.

Workings

Hint
Does the answer change = NO.

Answer
 

Workings

Hint
Make sure that you read the question carefully.

Answer
Kevin, since it was Kevin's mother and Kevin's brothers were Alpha and Beta.

Workings

Hint
A fathom is 6 feet.

Answer
Hours in a month.

Reasoning
A fathom is 6 feet, which is 1.8288 metres.

So there are 1000 ÷ 1.8288 ≈ 546.8 fathoms in a kilometre.

The shortest month has 28 x 24 hours = 672.

So even the shortest month has more hours than there are fathoms in a kilometre.