100+ Challenging math riddles to keep your mind sharp

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.

5/6 hours

Explanation :  

Let's call the amount of fuel in each car as "x".

Tony Stewart's car can drive for 4 hours with x amount of fuel, so his fuel consumption rate is x/4.
Jamie Mcmurray's car can drive for 5 hours with x amount of fuel, so his fuel consumption rate is x/5.

After a certain amount of time, they realize that the amount of fuel in Tony's car is 1/4th of the fuel in Jamie's car. So, x/4 = x/5 * 1/4.

Solving for x, we get x = 20.

So the amount of fuel in each car is 20.

Now, we can use the fuel consumption rate of each car to find out how long they have been racing.

Let's call the time they have been racing as "t".

Tony's car has x - x/4 * t = 20 - 20/4 * t = 20 - 5t amount of fuel left.
And Jamie's car has x - x/5 * t = 20 - 20/5 * t = 20 - 4t amount of fuel left.

We know that Tony's car has 1/4th of the fuel left in Jamie's car, so:
20 - 5t = (1/4) * (20 - 4t)
Expanding and simplifying, we get:
20 - 5t = 5 - t
25 - 6t = 5
t = 5/6 hours.

So, they have been racing for 5/6 hours.

Horse = 10, Cowboy Boot = 1 ,Horse Shoe= 2

Explanation :  

Horse = 10, Cowboy Boot = 1 ,Horse Shoe= 2

= Step 1 =
3 Horse = 30
= Horse = 10 .....(A)

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

= Step 3 =
2 Horse Shoe - 2 Cowboy Boot = 2
4 - 2 Cowboy Boot = 2
= Cowboy Boot = 1 ... (B)

= Step4 =
Cowboy Boot + Horse * Horse Shoe = 1+10*2 = 21 

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

Explanation :  

4100.
1000 + 40 = 1040
1040 + 1000 = 2040
2040 + 30 = 2070
2070 + 1000 = 3070
3070 + 20 = 3090
3090 + 1000 = 4090
4090 + 10 = 4100

Answer - 88

Explanation -

Let the YouTube icon be, Yt

Let the Facebook icon be, Fb

& The Instagram icon be, I

So rewriting the equations,

Equation(1); Yt + Yt + Yt = 21

Equation(2); Fb * Yt + Fb = 72

Equation(3); I * Fb + I = 80

Equation(4); (Yt + Fb) + Fb * I = ?

Now, initiating with equation(1);

Yt + Yt + Yt = 21

3Yt = 21

Yt = 7

Substitute the value of Yt in equation(2);

Fb * Yt + Fb = 72

Fb * 7 + Fb = 72

7Fb + Fb = 72

8Fb = 72

Fb = 9

Similarly, substitute the value in equation(3);

I * Fb + I = 80

I * 9 + I = 80

9 I + I = 80

10I = 80

I = 8

Now, moving for final equation(4), substitute the values in equation(4);

(Yt + Fb) + Fb * I = ?

= (7 + 9) + 9 * 8

= 16 + 72

(Yt + Fb) + Fb * I = 88

(Yt + Fb) + Fb * I = 88

Answer - ? = 43

Explanation - 

Let the pair of shoes be, S

Let the boy be, B

& The popcorn be, P

Converting the above equations in the form of the above terms.

Equation (1); S + S + S = 30

Equation (2); B + B + S = 20

Equation (3); 2P + 2P + B = 13

Equation (4); (0.5)S + (B + 2P + S) * P = ?

Now, solve equation(1);

S + S + S = 30

3S = 30

S = 10

Substitute the value of S, in equation(2)

B + B + S = 20

2B + 10 = 20

2B = 10

B = 5

Similarly, substitute B in equation(3);

2P + 2P + B = 13

4P + 5 = 13

4P = 8

P = 2

Now, substitute all the values for final equation(4);

(0.5)S + (B + 2P + S) * P = ?

= (0.5)10 + (5 + 2*2 + 10) * 2

= 5 + (5 + 4 + 10) * 2

(0.5)S + (B + 2P + S) * P = 5 + 38

(0.5)S + (B + 2P + S) * P = 43

Answer: B) 300 minutes

Explanation:

The time required in hours is 75 km divided by 15 km/h.

15 km/h equals 5 hours.

Converting hours to minutes: 5 × 60 = 300 minutes.

Answer: B) 14
Explanation: Let x
x be the number of candies Jagga has. Then, Gogo has 
x+8
x+8 candies. Together they have 

x+(𝑥+8)=36

x+(x+8)=36, which simplifies to 
2𝑥+8=36

2x+8=36.

 Solving for x

x, we get 
2x=28

2x=28 and 

x=14
x=14.

Answer: 53 liters

Explanation: The additional fuel needed is 150 - 97 = 53 liters.

Answer: 56 meters

Explanation: The length of Kushal's wall is 14 × 4 = 56 meters.