M4maths Previous Puzzles

01 Sep 2020 Area

The length of the diagonal and the breadth of a rectangular paper are 26 cm and 10 cm respectively. Find its perimeter (in cm).

OPtion

1) 68
2) 55
3) 44
4) 64
5) 63
6) 56
7) 66
8) 58
9) 72
10) None of these

Solution

Diagonal = D = 26cm
B = 10cm

L^2 = D^2 - B^2 = 26^2 - 10^2 = 676 - 100 = 576
L= 24

Perimeter = 2(24+10) = 68 cm

Correct Option: 1 Best Solution (0)

31 Aug 2020 Percentage

Mr. Kulbhushan spends 35% of his income on food, 25% on transportation and 80% of the remaining on house rent. What percent of his income he is left with ?

OPtion

1) 20
2) 36
3) 32
4) 16
5) 25
6) 6
7) 8
8) 7
9) 10
10) None of these

Solution

Let the total income be x.

Then, income left = (100 - 80)% of [100 - (35 + 25)] % of x = 20% of 40% of x = [(20/100) * (40/100) * 100] % of x = 8 % of x.

Correct Option: 7 Best Solution (5)

28 Aug 2020 Arithmetic

A page is torn from a book. The sum of the remaining digits is 1977. What are the page numbers on page torn from this book?

OPtion

1) 17, 18
2) 18, 19
3) 10, 11
4) 11, 12
5) 13, 14
6) 12, 13
7) 19, 20
8) 14, 15
9) 15, 16
10) None of these

Solution

Let the total pages are 'n'. We have
1 + 2 + 3 + .........+n = 1977
⇒ n(n+1)/2 = 1977
n (n+1) = 3954
The square nearest to 3954 is 3969.This is the square of 63. Hence, we will take n= 63.
Therefore, sum of the pages= n(n+1)/2 = 63*64/2= 2016
Missing number = 2016-1977 =39.
Now, we have to think of 2 consecutive numbers whose sum is 39.
x+x+1=39 ⇒ ×= 19, x+1= 20

Correct Option: 7 Best Solution (2)

27 Aug 2020 True Discount

The true discount on Rs. 1469 due 4 months hence is Rs. 113. The rate percent is?

OPtion

1) 25
2) 19
3) 13
4) 15
5) 18
6) 30
7) 10
8) 21
9) 24
10) None of these

Solution

Present Worth = 1469-113 =Rs. 1356

Rate = [100 x 113] / [1356 x (1/3)] =25%

Correct Option: 1 Best Solution (4)

26 Aug 2020 Area

A tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 225 paise per sq m is

OPtion

1) 558
2) 668
3) 568
4) 666
5) 888
6) 999
7) 1180
8) 1674
9) 750
10) None of these

Solution

Area to be plastered = [2(l+b)×h]+(l×b)

=[2(25+12)×6]+(25×12)=744sq.m

Cost of plastering = 744×225100=Rs.1674

Correct Option: 8 Best Solution (6)

25 Aug 2020 Marks

In JEECAT exam, a student scores four marks for every correct answer and loses one mark for every wrong answer. If Jaggu attempts all sixty questions and secures 130 marks, the no of questions Jaggu attempted correctly is :

OPtion

1) 44
2) 25
3) 46
4) 39
5) 36
6) 38
7) 45
8) 40
9) 43
10) None of these

Solution

Let the number of correct answers be X.

Number of incorrect answers = (60 – X).

4x – (60 – x) = 130

=> 5x = 190

=> x = 38

Correct Option: 6 Best Solution (11)

24 Aug 2020 Percentage

The price of a diamond is decreased from Rupees one crore to Rupees eighty five lakhs. Find the percentage of decrease.

OPtion

1) 14.29
2) 16.67
3) 25.00
4) 20.00
5) 12.50
6) 10.00
7) 15.00
8) 24.00
9) 19.00
10) None of these

Solution

10000000 - 8500000 = 1500000
% = 1500000*100/10000000 = 15%

Correct Option: 7 Best Solution (9)

21 Aug 2020 Handshakes

In a party there are 49 persons present. If each of them shakes hand with all the other persons,in total how many handshakes will take place?

OPtion

1) 1116
2) 1126
3) 1136
4) 1146
5) 1156
6) 1166
7) 1170
8) 1176
9) 1196
10) None of these

Solution

Out of 49 persons, the first person will shake hand with 48 persons.
The second person will shake hand with 47 persons (because he has already shaken hand with first person).
The third person will shake hand with 46 persons and so on. The second last person shakes hand with only one person. And last will shake hand with none
(because he has already shaken hand with all persons).
In order to find the total number of handshakes you have to add all the natural numbers from 1 to 48 i.e. ∑ 48.
∑48 = 48 x 49/2 = = 1176 handshakes.

Correct Option: 8 Best Solution (5)

20 Aug 2020 Number

A = (126a^2 + 113a + 11)/a; where A belongs to integer. How many integral solutions of A are possible?

OPtion

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

Solution

(126a^2 + 133a +11)/a = 126a + 133 + 11/a

Now we can see that whatever the value of ‘a’, 126a + 133 will always give an integral value.
So, it now depends upon 11/a only

=> a can have any integral value, which is a factor of 11.
The integers, which will satisfy this condition are ±1, ±11. Thus, in total,a can take 4 values.

Correct Option: 9 Best Solution (0)

19 Aug 2020 Mensuration

A rope is 89 cm long. It is cut into 3 pieces. The longest piece is 3 times as long as the middle-sized piece &

the shortest piece is 44 cm shorter than the longest piece. Find the length of the shortest piece (in cm).

OPtion

1) 12
2) 19
3) 13
4) 9
5) 18
6) 15
7) 10
8) 21
9) 4
10) None of these

Solution

Let the middle be x CM

Longest piece = 3x cm
Smallest piece = 3x - 44

x+3x+3x-44 = 89
7x = 133
x= 19
shortest piece = 3*19-44 = 13 cm

Correct Option: 3 Best Solution (5)