# 100+ Challenging math riddles to keep your mind sharp #### A quarter is one fourth of a dollar - Math Riddle

###### 121.Math Riddles

A quarter is one fourth of a dollar but Mr. Brainteaser has changed the equation as below : DOLLAR * 4 = QUARTER Can you replace each letter by a digit to make above solution correct ?

• `1830920`
```Explanation :  DOLLAR * 4 = QUARTER
457730 * 4 = 1830920```

#### Replace the question mark with number - Math Riddle

###### 122.Math Riddles

Which number should replace the question mark in the picture below ? • A.26
• B.30
• C.25
• D.45
A.26
• ```Explanation :  26
14 = 1^2 + 2^2 + 3^2
21 = 4^2 + 1^2 + 2^2
29 = 4^2 + 3^2 + 2^2
26 = 3^2 + 4^2 + 1^2```

#### There is a unique number - Math Riddle

###### 123.Math Riddles

There is a unique number which when multiplied by any number from 1 to 6, we will get the new number that contains same digits only. Can you find that number ?

• `142857`
```Explanation :  142857
142857 * 1 = 142857
142857 * 2 = 285714
142857 * 3 = 428571
142857 * 4 = 571428
142857 * 5 = 714285
142857 * 6 = 857142
These number are considered as cyclic numbers.```

#### For long they are racing ? - Math Riddle

###### 124.Math Riddles

Before the start of the car race, Tony Stewart and Jamie Mcmurray have the same amount of fuel in the car. With this fuel Tony Stewart can drive for 4 hours while Jamie can drive five hours. After a time they realize that amount of fuel left in Tony car is 1/4th of the fuel in Jamie car. For long they are racing ?

• `15/4 hours`
```Explanation :  15/4 hours
Let us say they drive for "t" hours and initial fuel is "f"

Amount of fuel used by Tony car is ft/4
Amount of fuel used by Jamie car is ft/5

As per given condition,
f - ft/5 = 4(f-ft/4)
Solving, t = 15/4 hours```

#### Horse Cowboy Boot and Horseshoe Viral - Math Riddle

###### 125.Math Riddles

Can you solve the equation by finding the value of A) Horse B) Cowboy boot C) Horseshoe • `Horse = 10, Cowboy-Boot = 1 ,HorseShoe= 2`
```Explanation :  Horse = 10, Cowboy-Boot = 1 ,HorseShoe= 2

= Step1 =
3Horse = 30
=> Horse = 10 .....(A)

= Step2 =
1Horse + 2HorseShoe + 2HorseShoe = 18
10 + 4HorseShoe =18
HorseShoe = 2 .....(C)

= Step3 =
2HorseShoe - 2Cowboy-Boot = 2
4 - 2Cowboy-Boot = 2
=> Cowboy-Boot = 1 ... (B)

= Step4 =
Cowboy-Boot+Horse*HorseShoe = 1+10*2 =>21 ```

#### Lena Dunham , Allison Williams, and Jemima Kirke - Math Riddle

###### 126.Math Riddles

Lena Dunham , Allison Williams, and Jemima Kirke are 3 daughters of a good mathematician "Geroge". When I asked George the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime.? How old are the daughters ?

•

```Explanation :  Lena Dunham : 2 , Allison Williams : 5 and Jemima Kirke : 7
Age diff : 7 2 is 5 , 7 5 is 2
and 5 2 is 3 which all are prime numbers```

#### Equation Math Puzzle

###### 127.Math Riddles

1000 + 40 + 1000 + 30 + 1000 + 20 + 1000 + 10 = ?

• A.5000
• B.4100
• C.3500
• D.6000
B.4100
• ```Explanation :  4100.
1000 + 40 = 1040
1040 + 1000 = 2040
2040 + 30 = 2070
2070 + 1000 = 3070
3070 + 20 = 3090
3090 + 1000 = 4090
4090 + 10 = 4100```