M4maths Previous Puzzles

17 May 2019 Percentage

In last assembly elections for Delhi state, party A, B AND C fought against each other and got 28, 45 and 21 percent of total votes respectively. The remaining percent of votes went to others. For 2019 assembly election, party A urges party C to have an alliance so that they can beat party B.

Below facts hold good for 2019 election:
1. There is a 2% increase in vote percent of party B when compared to its own vote percent of 2014. Note: This 2% increase is only in comparison to Party B's vote percentage of 2014 and not on overall.
2. If Party A and C are forming an alliance then party A will loose 20% of its own vote percentage from what it has got in 2014, this vote percentage will go to others
3. Party's C vote share will remain same as 2014 with or without alliance with party A
4. Also, given that the number of voters in 2014 and 2019 are same.

Assuming an alliance between party A and C is formed, what is the vote percent difference between the party B and the alliance formed by A & C?

OPtion

1) 2.2%
2) 2.3%
3) 2.4%
4) 2.6%
5) 2.5%
6) 2.7%
7) 2.8%
8) 2.9%
9) 3.0%
10) None of these

Solution

Vote Percent of Party B in 2019 = 1.02*45 = 45.9
Vote Percent of Party A in 2019 = 0.8*28 = 22.4
Vote Percent of Party C in 2019 = 21

Total vote percent of alliance A+C = 43.4%

Winning party is B and margin is = 45.9 - 43.4 = 2.5%

Correct Option: 5 Best Solution (3)

16 May 2019 Simple Interest

Gappu's great grandfather did a fixed deposit of Rs 50,000/- at the simple interest rate of 10% in 1949, grand mother also did a fixed deposit of 5,00,000/- at the simple interest rate of 8% in 1974 and father did a fixed deposit of 500,000,000/- at the simple interest rate of 7% in 1989.
All these fixed deposits are maturing in 2019. How much amount would Gappu get in 2019?
Assume that Gappu is the sole owner for these deposits made by his family ancestors. Also, assume that once invested fixed deposit's interest rate continues to be fixed at the initial rate throughout the investment tenure.

OPtion

1) 1551700000
2) 1553700000
3) 1554700000
4) 1552100000
5) 1555700000
6) 1556700000
7) 1552700000
8) 1558700000
9) 1559700000
10) None of these

Solution

Amount of great grandfather's investment in 2019 = 50,000 + (50,000*10*70)/100 = 4,00,000
Amount of grand mother's investment in 2019 = 5,00,000 + (5,00,000*8*45)/100 = 23,00,000
Amount of father's investment in 2019 = 500,000,000 + (500,000,000*7*30)/100 = 15500,00,000

In 2019, Gappu would get = 4,00,000 + 23,00,000 + 15500,00,000 = 1552700000

Correct Option: 7 Best Solution (3)

15 May 2019 Area

If the diagonal of a rectangle is 21cm long and its perimeter is 46 cm. Find the area of the rectangle.

OPtion

1) 30 sq.cm
2) 36 sq.cm
3) 48 sq.cm
4) 44 sq.cm
5) 50 sq.cm
6) 52 sq.cm
7) 42 sq.cm
8) 46 sq.cm
9) 54 sq.cm
10) None of these

Solution

Let length = x and breadth = y then

2(x+y) = 46 => x+y = 23
x²+y² = 21² = 441
now (x+y)² = 23²
=> x²+y²+2xy= 529
=> 441+ 2xy = 529
=> xy = 44

Area = xy = 44 sq.cm

Correct Option: 4 Best Solution (0)

14 May 2019 Average

The average weight of 45 students is 53 kgs . It was found later that the figure of 38kg was misprinted as 83kg for one of the students.
What is the correct average.

OPtion

1) 52
2) 53
3) 54
4) 51
5) 50
6) 48
7) 49
8) 47
9) 55
10) None of these

Solution

Total difference in sum of weight of 45 students = 38-83= 45 kg
so difference in average weight of 45 students = 45/45= 1 kg

so actual average weight is 53-1=52 kg

Correct Option: 1 Best Solution (3)

13 May 2019 Lift

Jack enters a lift on the 23rd floor, which is going up @ 18 floors/min speed. At the same time Jill

enters another lift on the 183rd floor which is going down @ 27 floors/min speed. At what floor will they be together?

OPtion

1) 64
2) 65
3) 67
4) 41
5) 43
6) 47
7) 97
8) 93
9) 95
10) None of these

Solution

Relative Speed = 18+27 = 45 floors/min
Relative Distance = 183 - 23 = 160 floors

Time to cover 160 floors with relative speed = 160*60/45 = 640/3 seconds

Floors travelled by Jack in 640/3 seconds = (18/60)*640/3 = 64
Floors on which they will meet = 23 + 64 = 87th
Option 10)

Correct Option: 10 Best Solution (0)

10 May 2019 Perfect Squares

How many factors of 1230356435 are perfect squares?

OPtion

1) 12
2) 16
3) 9
4) 8
5) 6
6) 14
7) 20
8) 15
9) 24
10) None of these

Solution

1230356435 = 5^1 * 7^5 *11^4

Any factor of this number should be of the form 5^a * 7^b * 11^c.

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

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

Total number of perfect squares = 1 * 3 * 3 = 9

Correct Option: 3 Best Solution (0)

09 May 2019 Probability

If two letters are taken at random from the word ABDOMEN, what is the probability that none of the letters would be vowels?

OPtion

1) 2/5
2) 3/7
3) 1/2
4) 1/6
5) 1/3
6) 4/7
7) 2/7
8) 3/10
9) 5/12
10) None of these

Solution

P(first letter is not vowel) = 4/7 = 4/7


P(second letter is not vowel) = 3/6 = 1/2


So, probability that none of letters would be vowels is = (4/7)×(1/2)= 2/7

Correct Option: 7 Best Solution (3)

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 (3)

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)