100+ Challenging Math riddles to keep your mind sharp page 3 of 9

Bees and Flowers Logic -Math riddle

31.Math Riddles

There are some lotus flowers in a pond and some bees are hovering around. If one bee lands on each flower one bee will be left; If two bees land on each flower one flower will be left; Then the number of flowers and bees respectively are

How many flowers and bees are there?

A.3,4
B.4,3
C.2,3
D.3,2

A.3,4

Explanation :  Let the number of flowers  = x
 if one bee lands on each flower Then one bee will be left So number of bees in this case =x*1+1=x+1
If two bees land on each flower then one flower will be left  so number of bees in this case 
=(x-1)*2=2x-2
we have 
x+1=2x-2
x=3
Number of flowers  =3
Number of bees =x+1=3+1=4

Magnifying Glass -Math riddle

32.Math Riddles

Jim was examining an angle measuring 14 and 1/2 degrees, using his magnifying glass that magnifies everything two times. Under the glass, how large would that angle measure?

Explanation :  14 and 1/2 degrees, because magnifying glass that magnifies everything two times

Laying Egg's -Math riddle

33.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?

Two dozen.

Explanation :  If you increase both the number of hens and the amount of time available four-fold (i.e., 1.5 times 4 equals 6), the number of eggs increases 16 times. 16 x 1.5 = 24.

Added to the sum of their squares is 109 -Math riddle

34.Math Riddles

There are two numbers whose product added to the sum of their squares is 109, and the difference of whose squares is 24. What are the two numbers?

5 and 7.

Explanation :  (5)Â² = 25(7)Â² = 49(5x7)+25+49=10949-25=24

Add five to twelve-Math riddle

35.Math Riddles

I add five to twelve, and get five. Why is this correct?

Explanation :  When it is 12 pm, adding five hours makes it 5 pm.

How many kids-Math riddle

36.Math Riddles

At a children's party, 10 kids had juice, 8 kids had cake, and 6 kids had juice and cake. How many kids were there at the party?

Twelve kids.

Explanation :  Six kids had juice and cake, leaving two out of the cake eaters that didn't have juice. As there were ten juicers, there must be twelve kids in total.

Men With Earing -Math riddle

37.Math Riddles

There is a certain club which is for men only. There are 600 men who belong to this club and 5% of these men wear one earring. Of the other 95% membership, half wear two earrings and the other half wear none. How many earrings are being worn in this club?

Six hundred.

Explanation :   We know that 5%, or 30 of the men are wearing one earring. Of the other 95%, or 570, we know that half are wearing two earrings and the other half none. This is the same as if they all wore one.

Bill's Age -Math riddle

38.Math Riddles

Eight years ago, Bill was eight times the age of his son Bill Jr. Today, if you add their ages together, they add up to 52. How old are Bill and his son?

Bill is 40, and Bill Jr. is 12.

Explanation :  Eight years ago, Bill Jr. was x years therefore Bill was 8x

Today

(x+8) +(8x+8) = 52

x+8 + 8x+8 = 52

9x + 16 = 52

9x = 52–16

9x = 36

Therefore x = 4

Bill Jr. is

x + 8 = 12

4 + 8 = 12 years old

Bill is

8x + 8 = 32 + 8

32 + 8 = 40 years old

Therefore 12 + 40 = 52 years.

Three matches are sitting on a table -Math riddle

39.Math Riddles

Three matches are sitting on a table. Without adding another make for three matches four. You are not allowed to break any of the matches. How can this be done?

Explanation :  Shape the 3 matches into a roman numeral four.

Nonstop Train -Math riddle

40.Math Riddles

A nonstop train leaves Moscow for Leningrad at 60 mph. Another nonstop train leaves Leningrad for Moscow at 40 mph. How far apart are the trains 1 hour before they pass each other?

Three times as old as my sister was -Math riddle

41.Math Riddles

One sister says of her younger sister: "Two years ago, I was three times as old as my sister was. In three years's time, I will be twice as old as my sister.? How old are they each now?

Explanation :  One way to solve this math  is to use even numbers: The elder sister will be twice as old as her younger sister in three year's  time. This immediately rules out the elder sister currently being 8, 11, and 14, so she must be 17, and the younger sister 7.

Creature and Fill tank -Math riddle

42.Math Riddles

There is a Creature which could double its size every day. So, if the Creature is put in a tank then it will fill the tank in 10 days. How many days would it take for the creature to fill 1/2 and 1/4 of the tank?

9 days to fill 1/2 and 8 days to fill 1/4 of the tank.

Explanation :  If the creature fills the tank in 10 days and it doubles every day, on the ninth day it would fill 1/2 the tank. Thus on the 8th day it will fill 1/4 of tank.

What is the next number -Math riddle

43.Math Riddles

What is the next number in the series? 7,645 5,764 4,576?

6,457.

Explanation :  The last digit is moved to the front to make the next number.

Sister and Brother -Math riddle

44.Math Riddles

A boy has as many sisters as brothers, but each sister has only half as many sisters as brothers. How many brothers and sisters are there in the family? A boy has as many sisters as brothers, but each sister has only half as many sisters as brothers. How many brothers and sisters are there in the family?

Explanation :  Four brothers and three sisters.

Two whole Positive Number-Math riddle

45.Math Riddles

What two whole, positive numbers that have a one digit answer when multiplied and a two digit answer when added?

100+ Challenging math riddles to keep your mind sharp