M4maths Previous Puzzles

08 May 2019 Percentage

In 2012, the price of arhar/toor daal increased by 50%, by what % should a housewife reduce the consumption of arhar/toor daal so that expenditure on arhar/toor daal can be same as before ?

OPtion

1) 20%
2) 15%
3) 25%
4) 40%
5) 50%
6) 33.33%
7) 45%
8) 60%
9) 66.66%
10) None of these

Solution

As price increase and consumption are inversely proportional,
if one increases by 1/x then other should reduce by 1/(x+1)
hence 50% is 1/2, consumption should reduce by 1/(2+1) = 1/3 = 33.33%

Correct Option: 6 Best Solution (3)

07 May 2019 Percentage

In April a Cricket team that played 50 games had won 40% of its game played. After a phenomenal winning streak this team raised its average to 60%.
How many minimum games must the team have won in a row to attain this average?

OPtion

1) 14
2) 15
3) 18
4) 20
5) 22
6) 33
7) 25
8) 35
9) 30
10) None of these

Solution

Number of games won when winning percent was 40% = 40*50/100 = 20 games

Let the winning streak be of x games

so ((x+20)/(x+50))*100 = 60
Solving we get: 10x + 200 = 6x + 300
=> 4x = 100
=> x = 25

Correct Option: 7 Best Solution (2)

06 May 2019 Number

If x and y are the two digits of the number 635xy such that this number is divisible by 83, then x*y is equal to:

OPtion

1) 36
2) 42
3) 48
4) 54
5) 56
6) 63
7) 72
8) 60
9) 70
10) None of these

Solution

On dividing 63500 by 83 we get = 765.06
Adding 1 to 765 we get 766

So the 5 digit number is 83*766 = 63578
Hence x = 7 and y=8

x*y = 56

Correct Option: 5 Best Solution (0)

03 May 2019 Stocks

The market value of a 9.5% stock, in which an income of Rs. 999 is derived by investing Rs. 10500, brokerage being 1/4 %, is:

OPtion

1) 99.21
2) 99.84
3) 99.59
4) 99.15
5) 99.16
6) 99.96
7) 99.75
8) 99.46
9) 99.65
10) None of these

Solution

For an income of Rs. 999, investment = Rs. 10500

For an income of Rs. 9.5, investment = Rs. (10500/999) * 9.5 = 99.84
For a Rs. 100 stock, investment = Rs. 99.84

Market value of Rs. 100 stock = Rs. 99.84 - 0.25 = Rs. 99.59

Option 3)

Correct Option: 3 Best Solution (0)

02 May 2019 Factors

How many factors of 534534400 are odd number?

OPtion

1) 12
2) 8
3) 16
4) 18
5) 25
6) 15
7) 30
8) 40
9) 24
10) None of these

Solution

534534400 = 2^8 * 5^2 * 17^4

Any factor of this number should be of the form 3^a * 5^b * 17^c.

For the factor to be a odd number a should be 0

b can take values 0, 1, 2
and c can take values 0, 1, 2, 3, 4

Total number of odd factor = 3 * 5 = 15

Correct Option: 6 Best Solution (2)

01 May 2019 Perfect Squares

How many factors of 105488578125 are perfect squares?

OPtion

1) 20
2) 48
3) 18
4) 60
5) 24
6) 16
7) 36
8) 32
9) 40
10) None of these

Solution

105488578125 = 3^9 * 5^6 * 7^3

Any factor of this number should be of the form 3^a * 5^b * 7^c.

For the factor to be a perfect square a,b,c have to be even.

a can take values 0, 2, 4, 6, 8
b can take values 0, 2, 4, 6
and c can take values 0, 2

Total number of perfect squares = 5 * 4 * 2 = 40

Correct Option: 9 Best Solution (0)

30 Apr 2019 Number

A two digit number is 4 times to its sum of digits. When 18 is added to the number, the digits will get reversed. Then what is that number?

OPtion

1) 36
2) 48
3) 12
4) 42
5) 60
6) 72
7) 18
8) 24
9) 27
10) None of these

Solution

Let the 2 digit number be yx
When 18 is added digits are reversed.
(10x+y)-(10y+x)=18
solving we get x-y=-2
There are so many possibilities of different values of x,y vix
(1,3),(2,4)(3,5),(4,6)(5,7),(6,8),(7,9)
But from the above possibilities, the condition satsfies is the number 24
2+4 = 6
=> 6*4 = 24

Correct Option: 8 Best Solution (5)

29 Apr 2019 Profit & Loss

By selling 48m of cloth, one gains the selling price of 12m. Find the gain percent?

OPtion

1) 33.33%
2) 25%
3) 50%
4) 30%
5) 27.33%
6) 60%
7) 36.66%
8) 24%
9) 27%
10) None of these

Solution

S.P of 48 m=48
S.P of 12 m=12
profit=12
C.P of 48 m = 48 - 12 = 36
(12/36)*100 = 33.33 %

Correct Option: 1 Best Solution (0)

26 Apr 2019 Percentage

A school has 18% students from Maharashtra, out of these 30% are Mumbai students. Find the total percentage of students from Mumbai ?

OPtion

1) 54%
2) 27%
3) 5.0%
4) 4.0%
5) 5.4%
6) 6.0%
7) 8.0%
8) 7.0%
9) 10%
10) None of these

Solution

Total percentage of students from Maharashtra = 18%
Percentage of Mumbai students among 18% of Maharashtra students = 30%
Total percentage of students from Mumbai = 30% of 18 = (30*18)/100 = 5.4%

Option 5)

Correct Option: 5 Best Solution (0)

25 Apr 2019 Time and Distance

Shaktiman saw a criminal at a distance of 75m. When Shaktiman started chasing him the criminal also started running. If the ratio of Speeds of Shaktiman to Criminal is 8:7. Then much distance did Shaktiman run to catch the Criminal?

OPtion

1) 420m
2) 425m
3) 475m
4) 520m
5) 433m
6) 4200m
7) 4215m
8) 4350m
9) 4275m
10) None of these

Solution

Let the distance traveled by criminal before he is caught be x

Time taken by Shaktiman = Time taken by Robber

(75 + x)/8 = x/7
=> x = 525 m
Distance travelled by Shaktiman = 525 + 75 = 600 m

Option 10)

Correct Option: 10 Best Solution (0)