Mathematical Puzzles are frequently asked in various competitive exams. These are based on various concepts of algebra, arithmetic, ratio & proportion, time & distance, etc. Here is a compilation of different maths puzzles grouped according to their level of difficulty. Each article contains a set of 10 mathematical puzzles with solutions. In this article, you will come across easy math puzzles devised to hone your mental aptitude.
Solve these easy math riddles and check your level of preparation:
Q.1. An elephant and a tiger were carrying full sacks on their backs. The elephant started complaining that his load was too heavy. The tiger said to him "Why are you complaining? If you gave me one of your sacks I'd have double what you have and if I give you one of my sacks we'd have an even amount." How many sacks were each of them carrying? Give the minimal possible answer.
Lets assume that the elephant was carrying E sacks and the tiger was carrying T sacks.
As the tiger told the elephant, "If you gave me one of your sacks I'd have double what you have."
T + 1 = 2 * (E-1)
T + 1 = 2E - 2
T = 2E - 3
The tiger also said, "If I give you one of my sacks we'd have an even amount."
T - 1 = E + 1
T = E + 2
Comparing both the equations,
2E - 3 = E + 2
E = 5
Substituting E=5 in any of above equation, we get T=7
Hence, the elephant was carrying 5 sacks and the tiger was carrying 7 sacks.
Q.2. On Monday,Kapoor ate half parantha. He ate half of what was left on Tuesday and so on. He followed this pattern for one week. How much of the parantha would he have eaten during the week?
Kapoor ate half parantha on Monday. On Tuesday, he would have ate half of the remaining parantha i.e. 1/4 of the original parantha. Similarly, he would have ate 1/8 of the original parantha on Wednesday and so on for the seven days.
Total parantha Kapoor ate during the week is
= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
= 99.22% of the original parantha
Q.3. Hari's age is three years more than four times Rakesh's age. After five years, Hari's age will be one year more than thrice Rakesh's age. What is Hari's present age?
Let Rakesh's present age is X years.
Hence, Hari's present age is (4X + 3) years.
After 5 years, Rakesh's age will be (X + 5) years and Hari's age will be (4X + 8) years.
But it is given that after 5 years Hari's age will be one year more than thrice the Rakesh's age.
(4X + 8) = 3 * (X + 5) + 1
4X + 8 = 3X + 16
X = 8
Therefore, Hari's present age is 35 years.
Q.4. The ratio of employees to managers is 7: 3. 70% of the employees and 30% of the managers take lunch in the canteen. What % of total workforce takes lunch in canteen?
Assume there are 7X employees and 3X managers
Total workforce taking lunch in canteen
= (7X) (70/100) + (3X) (30/100)
= 49(X/10) + 9(X/10)
Total workforce are = 7X + 3X = 10X
% of workforce taking lunch in canteen
= ((58X/10) * 100) / 10X
= 58 %
Q.5. What 5-digit number has the following features:
If we put the numeral 2 at the end of the number, we get a number which is three times a number if we put the numeral 2 at the beginning?
Assume there are 7X employees and 3X managers
Using an easy equation:
3(200000 + x) = 10x+2
(Adding 200000 puts a 2 at the front of a five-digit number, and multiplying by 10 and adding 2 puts a 2 at the end of a number)
Solving this gives:
10x+2 = 3(200000 + x)
10x+2 = 600000 + 3x
10x = 599998 + 3x
7x = 599998
x= 599998/7 = 85714
The answer is 85714.
Q.6. A three-digit whole number n is such that the last three digits of n2 are in fact the original number n. How many such n are there?
Looking at the last digit, the last digit must be either 0, 1, 5 or 6.
Then looking at the last two digits, the last two digits must be either 00, 01, 25 or 76.
Then looking at the last three digits, the last three digits must be either 000, 001, 625 or 376.
Out of those, only 625 and 376 are 3 digit numbers which satisfy the given condition.
Q.7. Rishab asked his Grandfather how old he was. Rather than giving him a straight answer, he replied: "I have 6 children, and there are 4 years between each one and the next. I had my first child (your Uncle Ravi) when I was 29. Now the youngest one (your Auntie Ramita) is 29 herself. That's all I'm telling you!" How old is Rishab's grandfather?
Rishab's grand father is 78 years old. Let's see why:
First child born: grand father is 29
Second child born: grand father is 33 (29 + 4)
Third child born: grand father is 37 (33 + 4)
Fourth child born: grand father is 41 (37 + 4)
Fifth child born: grand father is 45 (41 + 4)
Sixth child born:grand father is 49 (45 + 4)
When sixth child youngest one is 29: grand father is 78 (49 + 29).
Q.8. What is the smallest number which when divided by 35 leaves remainder 30 ,when divided by 45 leaves remainder 40 and when divided by 55 leaves remainder 50?
The easiest way is to find the Least Common Multiple of 35,45 and 55 subtract 5 from it. The LCM of , 35,45 and 55 is 3465. Hence, the required number is 3460.
Q.9. If Etti can swim 4 miles downstream (with the current) in a river in 20 minutes, & upstream 1 mile (against the current) in 15 minutes, how long would it take her to swim a mile in still water?
She is able to swim downstream at 12 miles an hour, & upstream at 4 miles an hour. so speed of boat in still water is (12+4)/2=8 miles per hour.
She can thus swim a mile in still water in 60/8=7.5 minutes.
In the first column, (10x6)-2 = 58.
In the second column,(11x7)-3 = 74
So, missing number = (12x8)-4 = 92. Hence, the answer is (d).