#141 - Calculate Sibling Family Riddle

In a family, there are many children. Every boy in the family has as many brothers as the sisters. However, each girl has twice number of brothers as that of sisters.

Can you calculate the number of siblings in the given family ?

View Answer Discuss

Suppose that the number of boys be "b" and number of girls be "g".

Now, each boy has equal number of brothers and sisters:
(b - 1) = g
=> (b - g) = 1 ------ (1)

In addition, each girl has twice as many brothers as sisters:
2 (g-1) = b
=> (2g - b) = 2 ------- (2)

From (1) and (2)
g = 3 and b = 4

Therefore, there are 4 boys and 3 girls in the family.

#142 - How Many Toffees Maths Problem

Roy needs to purchase 100 toffees from three different shops and he has exactly 100 rupees to do that which he must spend entirely. He must buy at least 1 toffee from each shop.

The first shop is selling each toffee at 5 paise, the second is selling at 1 rupee and the third is selling at 5 rupees.

How many toffees should he buy from each shop?

View Answer Discuss

Roy should buy 80 toffees from the first shop, 1 toffee from the second shop and 19 toffees from the third shop

#143 - Count Cartons Maths Problem

Adam can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into ?

View Answer Discuss

9

Five cartons for large chocolate boxes = 5 * 6 = 30 chocolate boxes.
Four cartons for small chocolate boxes = 4 * 9 = 36 chocolate boxes.
Thus total number of cartons required = 5 + 4 = 9.

#144 - Math Age Problem

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of son in months is the same as grandfather in years.
The age of the son in days is the same as father in weeks.

View Answer Discuss

The grand father is 84 years old.
The father is 49 years old.
The son is 7 years old.

#145 - Drive Time Maths Puzzle

Alpha and Beta have same amount of petrol in their respective cars. Alpha can drive for 4 hours whereas Beta can drive for 5 hours with the amount of petrol left.

Both of them start driving at the same time. After a few hours, they find out that the amount of petrol remaining in one of the cars is four times the other car.

Can you calculate for how long did they drive the cars?

View Answer Discuss

3 3/4 hours

Assume that the initial amount of petrol in each of the petrol tanks be P.
Now, let us assume that they drove for H hours.

In that case, the amount of petrol used by one car in H hours will be = P*H /4
The amount of petrol used by the other car will be = P*H/5

Therefore, the petrol left in one car = P - P*H / 4
Petrol left in the other car = P - P*H / 5

Now, according to the question,
P - P*H / 5 = 4 (P - P*H / 4)
=> H = 15 / 4 = 3 3/4 hours.

#146 - How Many Burgers Maths Problem

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours ?

View Answer Discuss

18

More hours => more burgers.
More boys => more burgers.

The time become twice (3 hours / 1.5 hours).
Boys become six times (9 / 1.5).

Number of burgers = 2 * 6 * Original(1.5)
= 18

#147 - Compare Quantity Puzzle

Suppose "s" represents the number of seconds in a day and "h" represents the number of hours in ten years (which will also include two leap years), can you calculate which quantity is greater from the two variables?

View Answer Discuss

S = 60 * 60 * 24 seconds = 86, 400 seconds.
H = (8 * 365 *24) + (2 * 366 *24) hours = 87, 648 hours

Clearly, H is greater than S even though not by much.

#148 - Letter To Number Puzzle

In the figure that has been attached with this question, each digit represents a digit. The similar letters carry the same integer value.Can you expose the original digits?

Letter To Number Puzzle
View Answer Discuss

See the picture for the answer. T = 1W = 3O = 8H = 9R = 0E = 4

#149 - Number Trivia

Can you find out which number multiplied by itself will give the output as 12345678987654321 ?

View Answer Discuss

1 * 1 = 1
11 * 11 = 121
111 * 111 = 12321
1111 * 1111 = 1234321
.
.
.
111111111 * 111111111 = 11=2345678987654321

#150 - Trivia Number Riddle

A special integer exists in mathematics that shows a special property. If you subtract any number from that integer, the result will always be divisible by the successor of that number completely.

Do you know what that integer is ?

View Answer Discuss

The required integer is -1.

For an example, let us subtract 7 from -1.

-1 - 7 = -8

Now the successor of 7 is 8 and (-8) is exactly divisible by 8.

You can try that for any number and it will hold true.