# 100+ Challenging math riddles to keep your mind sharp #### 300 ft. train travelling -Math riddle

###### 1.Math Riddles

A 300 ft. train is travelling 300 ft. per minute must travel through a 300 ft. long tunnel. How long will it take the train to travel through the tunnel?

• A.2 min
• B.3 min
• C. 4 min
• D.8 min
A.2 min
• ```Explanation :  Two minutes. It takes the front of the train one minute, and the rest of the train will take two minutes to clear the tunnel.
```

#### Three digit number fun - Math riddle

###### 2.Math Riddles

I am a three digit number. My second digit is four times bigger than the third digit. My first digit is three less than my second digit. Who am I? • A.151
• B.251
• C.131
• D.141
D.141
• ```Explanation :  141

Let third digit c be x

The second digit is four times as big as the third digit,

Thus 2nd digit b = 4x

the first digit is three less than the second digit

Thus 1st digit a = (4x  3) if we put 1 only in place of x then it fulfills all the requirments.```

#### 100 pairs of dogs - Math riddle

###### 3.Math Riddles

There are 100 pairs of dogs in a zoo; a pair of babies are born for each dog. Unfortunately, 23 of the dogs gone . How many dogs are left in total?

• A.1000
• B.900
• C.977
• D.277
C.977
• ```Explanation :  The answer is 977 as  100 x 2 = 200;
200 + 800 = 1,000;
1000-23=977
```

#### Miguel and Leila age -Math riddle

###### 5.Math Riddles

When Miguel was 6 years old, his little sister, Leila, was half his age. If Miguel is 40 years old today, how old is Leila?

• `37`
`Explanation :  She is 37 years old. Leila's age was 3 when Meguel age was 6. so age difference is 3. now she is 40 so her sister's age must be 40-3 = 37. `

#### Hen and Egg cool -Math riddle

###### 6.Math Riddles

If a hen and a half lay an egg and a half in a day and a half, how many eggs will half a dozen hens lay in half a dozen days?

• A.Two
• B.Three
• C.Four
• D.Five
A.Two
• `Explanation :   Two dozen Two dozen. If you increase both the number of hens and the amount of time available four fold, the number of eggs increases 16 times. 16 x 1.5 = 24.`

#### Substract five from 25 -Math riddle

###### 7.Math Riddles

What's the maximum number of times you can subtract five from 25?

• A.One
• B.Two
• C.Three
• D.Four
A.One
• `Explanation :  Only once. This is because when you subtract five the first time, 25 becomes 20, then 15, and so on.`

#### Leon and Turtle Aquarium - Math riddle

###### 8.Math Riddles

Leon works at the aquarium. When he tries to put each turtle in its own tank, he has one turtle too many. But if he puts two turtles per tank, he has one tank too many. How many turtles and how many tanks does Leon have?

• A.1,4
• B.2,1
• C.3,4
• D.4,2
C.3,4
• ```Explanation :
1 turtle in each tank = 1 turtle too many

2 turtles in each tank = 1 tank too many

Using one of the better known heuristic to solve this question

Before that, we know that:

2 turtles in each tank = 1 tank too many

2 turtles in each tank = 2 turtles short

First, find the difference in the number of turtles in the two scenarios:

First scenario = 1 turtle too many

Second scenario = 2 turtles short

Difference in turtles = 1 - (- 2)

Difference in turtles =  3

Second, find the difference in the distribution of turtles:

First scenario = 1 turtle each tank

Second scenario = 2 turtles each tank

Difference in turtle = 2 - 1

Difference in turtles = 1

Find the number of tanks:

Number of tanks = 3 ÷ 1

Number of tanks = 3

Find the number of turtles:

Using the first scenario, there was one turtle too many

Number of tanks = 3

Number of turtles = 3 + 1

Number of turtles = 4

There are 4 turtles and 3 tanks.```

#### Guess the price of shoes and hoodie -Math riddle

###### 9.Math Riddles

The total cost of a pair of shoes and a hoodie is \$150. The hoodie cost \$100 more than the pair of shoes. How much does each item cost?

• `\$125,\$25`
```Explanation :  Given that total cost of a pair of shoes and hoodie = \$150
The hoodie cost \$ 100 more than the pair of shoes
here we need to calculate cost of pair of shoes and hoodie
let x and y be the costs of the shoes and hoodie
from given data x + y = 150 _ (1)
hoodie cost is \$100 more than pair of shoes
y - x  = 100 _ (2)
add (1) and (2) ?   x + y + y - x = 150 + 100
=  2y = 250
=  y = 125
y = 125 =  x + 125 = 150
=   x  =  25
cost of pair of shoes = \$25 and cost of hoodie =\$125
```

#### Equation Math riddle

###### 10.Math Riddles

How can you add eight fours together so the total adds up to 500?

• `444 + 44 + 4 + 4 + 4 = 500`
`Explanation :  444 + 44 + 4 + 4 + 4 = 500`

#### Men and tables count -Math riddle

###### 11.Math Riddles

If four men can build four tables in four hours, how many tables can eight men build in eight hours?

• `16`
```Explanation :  16 tables
4 men 4 hours 4 tables
So 1 man makes 1 table in 4 hour
1 man will build 2 tables in 8 hours
8 men will build 8*2=16 tables in 8 hours.
```

#### Easy Math Riddle of Three Brothers - Math riddle

###### 12.Math Riddles

Three brothers live in a farm. They agreed to buy new seeds: Adam and Ben would go and Charlie stayed to protect fields. Ben bought 75 sacks of wheat in the market whereas Adam bought 45 sacks.

At home they split the sacks equally. Charlie had paid 1400 dollars for the wheat. How much dollars did Ben and Adam get of the sum considering equal split of the sacks?

• `Ben \$1225, Adam \$175`
```Explanation :  Every farmer's part is 1/3(45+75) = 40 sacks.
Charlie paid \$1400 for 40 sacks, then 1 sack costs \$1400/40 = \$35/sack.

Ben got \$35*(75-40)=35*35 = \$1225.```

#### Grand father, Father and Son -Math riddle

###### 14.Math Riddles

A grandfather, two fathers, and two sons went to the movie theater together, and everyone bought one movie ticket each. How many tickets did they buy in total?

• `3`
`Explanation :  Three (the grandfather is also a father and the father is also a son).`

#### How Many Ducks ? -Math riddle

###### 15.Math Riddles

There are two ducks in front of two other ducks. And, there are two ducks behind two other ducks. There are two ducks beside two other ducks. How many ducks are there?

• `4`
`Explanation :  4 ducks (in a square).`