Math Riddles

These Math Riddles are based on math concepts and can be solved with a bit of math and logic. These fun riddles can surely give you a tough time.

Two Trains and a Fly

Two trains travel toward each other on the same track, beginning 100 miles apart. One train travels at 40 mph (miles per hour); the other travels at 60 mph.

A fly starts flight at the same location as the faster train, flying at a speed of 90 mph. When it reaches the slower train, it turns around, flying the other direction at the same speed. When it reaches the faster train again, it turns around, and so on. When the trains meet, how far will the fly have flown?

Riddle Answer

River Crossing – Wolf, Sheep, Cabbage

A farmer must transport a wolf, a sheep and cabbage from one side of a river to another using a boat. But in crossing the river by boat, the farmer could carry only himself and a single item – the wolf, the sheep or the cabbage.

If left together, the wolf would eat the sheep, or the sheep would eat the cabbage.

How can the farmer transport the wolf, the sheep and the cabbage across the river without losing any of them?

Riddle Answer

Counterfeit Money

A man goes into a barber shop and gets a haircut for $15. He pays the barber with a $20 bill, but the barber doesn’t have change. The barber goes to the neighboring flower shop and trades the $20 bill for a $10 dollar bill and two $5 bills. Then he gives the man his $5 in change.

Later the lady from the flower shop confronts the barber and tells him that the $20 bill he gave her was counterfeit money. The barber agrees and he gives the lady a different $20 bill.

Later that day he tries to figure out how much money he lost. How much money did the barber lose?

Riddle Answer