M4maths Previous Puzzles

07 Nov 2018 Diwali Puzzle - Happy Deepawali

Sheelu has following crackers kept in a bag:
3 pieces of Anar,
5 pieces of Chakri,
7 pieces of Rocket and
4 pieces Chocolate Bomb

On the day of Diwali, he randomly pulls out one cracker (which ever comes to his hand first) from the bag.

What is the probability that it was a Chakri?

OPtion

1) 3/19
2) 3/20
3) 7/20
4) 7/19
5) 4/19
6) 6/19
7) 5/19
8) 5/20
9) 4/20
10) none of these

Solution

Total number of crackers = 3+5+7+4= 19
Total number of chakris = 5

Probability = 5/19

Correct Option: 7 Best Solution (0)

06 Nov 2018 Series

3, 70 , 247, 618, ?
Find the next term

OPtion

1) 1271
2) 1251
3) 1331
4) 1301
5) 1291
6) 1311
7) 1321
8) 1261
9) 1281
10) None of these

Solution

Series is formed as shown below

2^4 - 13 = 3
3^4 - 11 = 70
4^4 - 9 = 247
5^4 - 7 = 618
6^4 - 5 = 1291

3, 70 , 247, 618, ?
Option 5)

Correct Option: 5 Best Solution (0)

05 Nov 2018 Simple Interest

At what simple interest rate percent per annum will a sum of money triple in 21 years.

OPtion

1) 9.50
2) 9.52
3) 8.33
4) 9.50
5) 9.25
6) 9.14
7) 9.75
8) 8.75
9) 9.66
10) None of these

Solution

SI = PRT/100

SI = 2P

So 2P = P*R*21/100
= R= 200/21 = 9.52
Option 2)

Correct Option: 2 Best Solution (0)

02 Nov 2018 Age

A father said to his son, "I was as old as you are at the present at the time of your birth". If the father's age is 52 years now, what was the son's age twenty three years back?

OPtion

1) 23
2) 22
3) 03
4) 20
5) 21
6) 04
7) 02
8) 01
9) 00
10) None of these

Solution

Let the sons current age be x
So fathers age x years back when son was born => 52-x = x
Solving we get x = 26
21 Years back son's age = 26-23 = 3 years

Option 3)

Correct Option: 3 Best Solution (3)

01 Nov 2018 ODD Number

How many factors of 953990136 are odd numbers?

OPtion

1) 60
2) 36
3) 72
4) 64
5) 30
6) 54
7) 128
8) 256
9) 96
10) None of these

Solution

953990136 = 23^3 * 11^2 * 3^4 * 2^3

Any factor of this number should be of the form 23^a *11^b * 3^c * 2^d

For the factors of this number to be an odd number d should be 0

a can take values 0, 1, 2, 3
b can take values 0, 1, 2
c can take values 0, 1, 2, 3, 4
d can take values 0

Total number of odd factors = 4*3*5*1= 60

Option 1)

Correct Option: 1 Best Solution (0)

31 Oct 2018 Simple Interest

Divide Rs. 9516 into 3 parts so that their amount after 2,3 and 4 years respectively may be equal, the rate of interest being 5% per annum at simple interest. The product of first and third part is

OPtion

1) 10555232
2) 10054232
3) 10053232
4) 10052232
5) 10015232
6) 10055222
7) 10055212
8) 10055252
9) 10055232
10) None of these

Solution

Let the parts be x, y and z
x + (x * 2 * 5/100) = y + (y * 3 * 5/100) = z + (z * 4 * 5/100)
11x/10 = 23y/20 = 6z/5 = k
x = 10k/11, y = 20k/23, z = 5k/6
But x + y + z = 16653
10k/11 + 20k/23 + 5k/6 = 9516
k = 3643.2
x*z = (10/11)*3643.2 * 5/6*3643.2= 10055232
Option 9)

Correct Option: 9 Best Solution (1)

30 Oct 2018 Profit & Loss

A shopkeeper marks up his goods by 35% and gives a discount of 20%. Apart from this, he uses a faulty balance also, which reads 1000 gm for 850 gm. What is his net profit percentage?

OPtion

1) 27.50
2) 25.50
3) 23.00
4) 22.06
5) 21.05
6) 27.06
7) 20.75
8) 19.77
9) 18.66
10) None of these

Solution

Let CP of 1000gm goods be Rs. 100
Then CP of 850 gm good is Rs 85

SP without discount is 35% of CP = 135
SP with 20% discount = 135 - 27 = Rs. 108

Now, shopkeeper is giving 850 gm of good instead of 1000gm
So CP = 85 and SP = 108

Profit = 108 - 85 = 23
Profit% = (23/85)*100 = ~ 27.06%

Correct Option: 6 Best Solution (0)

29 Oct 2018 Series

What is the next term of following series:
21, 34, 55, 89, 144,

OPtion

1) 259
2) 259
3) 257
4) 233
5) 295
6) 384
7) 288
8) 267
9) 287
10) None of these

Solution

Series is formed by Fibonacci numbers starting at 21 and 34 so next number is 144 + 89 = 233
Option 4)

Correct Option: 4 Best Solution (4)

26 Oct 2018 Profit and Loss

"A shopkeeper sells his goods at cost price but uses a weight of
790 gm instead of kilogram weight. What is his profit percentage?"

OPtion

1) 28.12
2) 27.21
3) 28.21
4) 29.31
5) 26.21
6) 25.21
7) 26.58
8) 29.12
9) 28.02
10) None of these

Solution

Let the CP of 1000 gm (1 kg) be Rs. 1000
Then CP of 790 gm = Rs 790
SP of 790gm = Rs 1000

Profit = (1000-790)*100/790 = (210/790)*100 = 26.58

Option 7)

Correct Option: 7 Best Solution (4)

25 Oct 2018 Discount

The marked price of a t-shirt is Rs.786. A shopkeeper offers three successive discount of 5%, 10% and 15%. How much will you have to pay, finally?

OPtion

1) 571.23
2) 555.79
3) 495.22
4) 577.22
5) 517.79
6) 496.79
7) 499.79
8) 501.79
9) 580.79
10) None of these

Solution

Price after 1st Discount = 786*95/100 = 746.7

Price after 2nd Discount = 746.7*90/100 = 672.03


Price after 3rd discount = 672.03*85/100 =571.23


Hence Option 1)

Correct Option: 1 Best Solution (8)