100+ Challenging math riddles to keep your mind sharp

Explanation :  

100
30+30+30=90
30+100+100=230
80+100+30=210
50-30+80= 100

    30

    Explanation :  

    There can be multiple solutions to this problem. 
     Listing three of them
    A) 11+13+6(rotating 9) = 30
    B) 11+13+3! = 30
    c) 11.5+5.5+13 = 30

    $2,000 

    Explanation :  

    $2000
    at first she bought it for 12000 and sold it 13000
    Profit from 1st transaction = $1000 (13000-12000)
    next day she bought it for 14000 and sold it for 15000
    Profit from 2nd transaction = $1000 (15000-14000)
    So the overall profit will be = (1st + 2nd )(1000+ 1000 )$2000

Explanation :  

A total of 90 students are in the sports group.

30 students play football.
40 students play Volleyball.
25 students play basketball.

15 students play both football and volleyball.
10 students play both football and basketball.
8 students play both volleyball and basketball.

5 students play all the three games.

Now, we will subtract the number of students playing each game from the total number of students in the group to find the number of students who are not playing any of the games.

First, let's find the number of students who are playing at least one game.

30 (students playing football) + 40 (students playing volleyball) + 25 (students playing basketball) - 15 (students playing both football and volleyball) - 10 (students playing both football and basketball) - 8 (students playing both volleyball and basketball) + 5 (students playing all three games) = 63

So, 63 students are playing at least one game.

Therefore, 90 (total number of students in the sports group) - 63 (students playing at least one game) = 27 students are not playing any of the games.

Explanation :  

Let us assume 
Carriage = 2, the Car = 3 and the Bus = 6
6+3+2= 3+3+3
If we remove carriage it will be balancedCarriage = 2, the Car = 3 and the Bus = 6
6+3+2= 3+3+3
If we remove carriage it will be balanced

Explanation :  

First Equation
1Red Flower + 1Red Flower + 1Red Flower = 60
Hence, 1Red Flower = 20
Second Equation
Red Flower + 5Blue Petals + 5Blue Petals = 30
20 + 10Blue Petals = 30
10Blue Petals = 10
Hence 1Blue Petals = 1
Third Equation
5Blue Petals + 2Yellow Flower = 3
5 + 2Yellow Flower = 3
2Yellow Flower = 2
Hence, 1Yellow Flower = 1
Required
Yellow Flower + Red Flower + 4Blue Petals = ?
Hence, 1 + 20 + 4 = 25

3 lbs.

Explanation :  

If the balance was equal when one soap was on one side and the other soap and a 3/4 pound weight were on the other side, we can use this information to find the weight of the soap.

Let's call the weight of the soap "x". Then, when one soap was on one side, the weight on the other side was (3/4) + (3/4) * x. Since the balance was equal, the weight of the two sides must be equal, so we can set them equal to each other and solve for x:

x = (3/4) + (3/4) * x

Solving for x, we get:

x = 3/4 + 3/4x

Subtracting 3/4x from both sides:

1/4x = 3/4

Dividing both sides by 1/4:

x = 3

So the weight of each soap is 3 pounds.

848

Explanation :  
Clue 1: Its first digit is of no use.
The digit '0' at the start of the number is of no use.

Clue 2: Its second and fourth digit is the mirror image of each other.
The number '8' is the only digit that is the mirror image of itself.

Clue 3: The third digit is half the second.
4 is half of 8

Explanation :  

8m
From green bar, we can deduce that
the height of vertical bar = 2/3 of uninterrupted shadow length of the bar.
Therefore shadow of 6m of red bar indicates the height of 4m.
The remaining red bar casts a direct 1:1 vertical projection on the wall.
Therefore total length = 4m + 4m = 8m.

Explanation :  

Logic Used: Sum the numbers and then subtract the two digits to get the desired answer.
12 + 13 + 7 => 32 => 3-2 => 1
15 + 16 + 11 =>42 => 4-2 => 2
17 + 18 + 16 = 51 => 5-1 => 4

39

Explanation :  

45-6 = 78 / 2 = 39 * 1

A = 4
B = 5
C = 6
D = 7
E = 8
F = 2
G = 3
H = 9
I = 1

So below equation can be solved as:
AB - C = DE / F = GH * I
45 - 6 = 78/2 = 39 * 1
39 = 39 = 39.

Explanation :  

60
V + II   VI = 10
= I = 10
IV   X + VIII = 20
= II = 20
IV   VII + VI = 30
= III = 30
I + II + III = 10 + 20 + 30

62

Explanation :  16 x 14 / 4 + 6 = 62

1830920

Explanation :  

DOLLAR * 4 = QUARTER
457730 * 4 = 1830920

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