M4maths Previous Puzzles

21 Feb 2019 Combination

There are 31 students in a class, number of girls is one more than number of guys. we need to form a team of four students. all four in the team cannot be from same gender and number of girls and guys in the team should NOT be equal. How many ways can such a team be made?

OPtion

1) 15680
2) 15480
3) 15280
4) 15180
5) 15380
6) 15080
7) 15600
8) 15580
9) 15880
10) None of these

Solution

boys=15 and girls=16 now the combinations are {girl,girl,girl,boy} or {boy,boy,boy,girl}
so 16c3*15c1 + 15c3*16c1 = 560*15 + 455*16 = 15680

Correct Option: 1 Best Solution (6)

20 Feb 2019 Profit & Loss

If a shopkeeper purchases cashew-nuts at Rs. 700 per kg. and sells it at Rs 45 per 50 gms, then he will have how much profit or loss percentage?

OPtion

1) 20.00 % profit
2) 28.07 % profit
3) 28.57 % loss
4) 22.57 % profit
5) 24.87 % profit
6) 29.98 % profit
7) 28.57 % profit
8) 26.57 % profit
9) 27.87 % profit
10) None of these

Solution

The Cost price of 1 kg cashew nuts = Rs.700
Cost price of 50 g of cashew nut = (700*50)/1000 = 35
The selling price of 50 g cashew nuts = Rs.45
Profit = Selling Price -Cost price = 45-35 = 10
Profit % = Profit x 100/Cost price
Profit % = 10 x 100/35 = 28.57% profit
Hence, the answer is 28.57% profit

Correct Option: 7 Best Solution (0)

19 Feb 2019 Time and Distance

Shaktiman saw a criminal at a distance of 10m. When Shaktiman started chasing him the criminal also started running. If the ratio of Speeds of Shaktiman to Criminal is 12:9. Then how much distance did Shaktiman run to catch the Criminal?

OPtion

1) 360m
2) 320m
3) 370m
4) 349m
5) 340m
6) 380m
7) 375m
8) 325m
9) 335m
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

(10 + x)/12 = x/9
=> 30 + 3x = 4x
=> x = 30m
Distance traveled by Shaktiman = 30+10 = 40m

Option 10)

Correct Option: 10 Best Solution (0)

18 Feb 2019 Speed & Distance

A train having a length of 360 m passes a post in 27 seconds. How long will it take to pass a platform having a length of 940 m?

OPtion

1) 96.00 sec
2) 97.50 sec
3) 97.00 sec
4) 98.50 sec
5) 96.50 sec
6) 95.21 sec
7) 96.12 sec
8) 99.50 sec
9) 98.20 sec
10) None of these

Solution

Time taken to cross post=length of train/speed of train
so speed of train=360/27 m/sec

time to cross platform= (length of train+length of platform) / speed of train
time = (360+940)/(360/27) = 97.5 sec

Correct Option: 2 Best Solution (6)

15 Feb 2019 Area

If the diagonal of a rectangle is 14cm long and its perimeter is 32 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) = 32 => x+y = 16
x²+y² = 14² = 196
now (x+y)² = 16²
=> x²+y²+2xy= 256
=> 196 + 2xy = 256
=> xy = 30

Area = xy = 30 sq.cm

Correct Option: 1 Best Solution (0)

14 Feb 2019 Valentine's Day

Four boys each sent a card to a different girl.

Rahul did not send a card to Aaliyah
Shubham sent a card to either Gehana or Pankhudi
Gehana did not receive a card from Amit or Ricky
Neither Amit nor Ricky sent a card to Ishika
Ricky would never send a card to Aaliyah
Pair up the boys and girls?

OPtion

1) Rahul-Pankhudi, Shubham-Gehana, Amit-Ishika, Ricky-Aaliyah
2) Rahul-Pankhudi, Shubham-Ishika, Amit-Gehana, Ricky-Aaliyah
3) Rahul-Ishika, Shubham-Pankhudi, Amit-Gehana, Ricky-Aaliyah
4) Rahul-Aaliyah, Shubham-Pankhudi, Amit-Gehana, Ricky-Ishika
5) Rahul-Gehana, Shubham-Aaliyah, Amit-Pankhudi, Ricky-Ishika
6) Rahul-Aaliyah, Shubham-Gehana, Amit-Pankhudi, Ricky-Ishika
7) Rahul-Ishika, Shubham-Aaliyah, Amit-Gehana, Ricky-Pankhudi
8) Rahul-Ishika, Shubham-Gehana, Amit-Aaliyah, Ricky-Pankhudi
9) Rahul-Gehana, Shubham-Pankhudi, Amit-Aaliyah, Ricky-Ishika
10) None of these

Solution

Lets make a matrix of possible combinations based on given options

Note X depends a combination which is not possible
* denotes the actual combination
A G P I
R X *
S *
A * X X
R X X * X

So the right answer is:
Rahul-Ishika, Shubham-Gehana, Amit-Aaliyah, Ricky-Pankhudi

Correct Option: 8 Best Solution (0)

13 Feb 2019 Calendar

Two brothers were expected to return here on the same day. Hardik returned 3 days earlier but Kunal returned 5 days later. If Hardik returned on Tuesday, what was the expected day when both the brothers were to return home and when did Kunal Return?

OPtion

1) Wednesday, Sunday
2) Friday, Thursday
3) Thursday, Tuesday
4) Saturday, Wednesday
5) Friday, Tuesday
6) Sunday, Wednesday
7) Friday, Wednesday
8) Saturday, Thursday
9) Monday, Friday
10) None of these

Solution

Answer is Friday, Wednesday
Hardik returned on Tuesday -i.e. 3 days earlier
so actual day to return home is Friday.
Kunal returned after 5 days so Wednesday

Correct Option: 7 Best Solution (3)

12 Feb 2019 Speed & Distance

A man has hurt his leg and is walking at 3/4th of the speed, he reaches his office late by 90 minutes. What is the usual time?

OPtion

1) 3 hours
2) 1.5 hours
3) 2 hours
4) 4.5 hours
5) 2.25 hours
6) 4 hours
7) 2.75 hours
8) 2.5 hours
9) 3.5
10) None of these

Solution

S1:S2=1:(3/4)
Since speed and time are inversely proportional. So t1:t2=3/4:1=3:4
Now,diff in time is 1.5 hrs. So,
4x-3x=1.5
X=1.5
So usual time is 3x = 4.5 hours
Option 4)

Correct Option: 4 Best Solution (5)

11 Feb 2019 Series

28, 38, ?, 62, 70, 77

OPtion

1) 50
2) 48
3) 51
4) 47
5) 52
6) 54
7) 46
8) 49
9) 53
10) None of these

Solution

28 + 2 + 8 = 38
38 + 3 + 8 = 49
49 + 4 + 9 = 62
62 + 6 + 2 = 70
70 + 0 + 7 = 77

Correct Option: 8 Best Solution (0)

08 Feb 2019 Prime Number

The sum of prime numbers between 0 to 20 is:

OPtion

1) 48
2) 75
3) 46
4) 67
5) 65
6) 64
7) 77
8) 69
9) 70
10) None of these

Solution

Sum of 2, 3, 5, 7, 11, 13, 17, 19 = 77

Correct Option: 7 Best Solution (0)