M4maths Previous Puzzles

24 Sep 2020 Mensuration

A string is 94 cm long. It is cut into 3 pieces. The longest piece is 4 times as long as the middle-sized piece

& the shortest piece is 59 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 size string be x CM

Longest piece = 4x cm
Smallest piece = 4x - 59

x+4x+4x-59 = 94
9x = 153
x= 17
shortest piece = 4*17- 59 = 9 cm

Correct Option: 4 Best Solution (0)

23 Sep 2020 Arithmetic

Mr. Ramanujam asked his students to find the sum of all pages of their maths book. Chatur gave the answer as 643.The teacher told him that he has not added one page.
Find the page number which the Chatur forgot to add?

OPtion

1) 24
2) 25
3) 16
4) 19
5) 36
6) 21
7) 22
8) 23
9) 27
10) None of these

Solution

1 + 2 + 3 + .........+n = 640
⇒ n(n+1)/2 = 640
⇒ n(n + 1) = 1280 ⇒
-> n^2 = 1280.
Now, the perfect square closest 1280 is 1296, which is the square of 36.

Sum will be -
36*37/2 = 666

As the given sum is 643, so the Chatur forgot to add page number 666 - 643 = 23.

Correct Option: 8 Best Solution (0)

22 Sep 2020 Percentage

Pappu has to obtain 33% of the total marks to pass. He got 115 marks and failed by 50 marks. The maximum marks are :

OPtion

1) 300
2) 375
3) 370
4) 450
5) 600
6) 500
7) 360
8) 350
9) 550
10) None of these

Solution

Given that the Pappu got 115 marks and still he failed by 50 marks

=> The minimum pass mark = 115 + 50 = 165

Given that minimum pass mark = 33% of the total mark

=> total mark =33/100 =165

=> total mark = 16500/33 = 500

Correct Option: 6 Best Solution (0)

21 Sep 2020 Capacity

To fill a bucket, 25 jugs of water is required. How many jugs of water will be required to fill the same bucket if the capacity of jug is reduced to two-fifth of its present ?

OPtion

1) 10
2) 5
3) 15
4) 20
5) 40
6) 48
7) 62.5
8) 56
9) 58
10) None of these

Solution

Let the capacity of 1 jug = x.
Then, capacity of bucket= 25x.


New capacity of bucket = (2/5)x
Required no of buckets = 25x/(2x/5) = 62.5

Correct Option: 7 Best Solution (2)

18 Sep 2020 RANK

What is the Rank of the word KETCHIKAN in the dictionary of words formed by the letters of the word KETCHIKAN ?

OPtion

1) 111353
2) 112353
3) 113353
4) 114353
5) 115853
6) 115352
7) 115351
8) 115353
9) 115349
10) None of these

Solution

100800 + 10080 + 4320 + 120 + 24 + 6 + 2 + 0 + 0 +1 = 115353

Correct Option: 8 Best Solution (2)

17 Sep 2020 Number

A = (225a^2 + 45a + 10)/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

(225a^2 + 45a +10)/a = 225a + 45 + 10/a

Now we can see that whatever the value of ‘a’, 225a + 45 will always give an integral value.
So, it now depends upon 10/a only

=> a can have any integral value, which is a factor of 10.
The integers, which will satisfy this condition are ±1, ±2, ±5, ±10. Thus, in total,a can take 8 values.

Correct Option: 5 Best Solution (4)

16 Sep 2020 Area

The area of a circle is 1386 cm². What is its circumference (in cm).

OPtion

1) 300
2) 275
3) 270
4) 132
5) 245
6) 250
7) 280
8) 190
9) 155
10) None of these

Solution

Pi*r^2 = 1386
r^2 = 1386 * 7/22 = 441
r = 21

Circumference = 2*pi*r = 2*22/7 * 21 = 132

Correct Option: 4 Best Solution (0)

15 Sep 2020 Percentage

If 20% of a = b, then b% of 20 is the same as :

OPtion

1) 10% of a
2) 2% of a
3) 16% of a
4) 40% of a
5) 8% of a
6) 4% of a
7) 8% of a
8) 6% of a
9) 16% of a
10) None of these

Solution

20% of a = b

=> (20/100) * a = b

b% of 20 =(b/100) x 20 = [(20a/100) / 100] x 20= 4a/100 = 4% of a.

Correct Option: 6 Best Solution (0)

14 Sep 2020 Cost Price

If the cost price of a Mobile is first decreased by 25% and then increased by 20%, then the net change in the price will be :

OPtion

1) 9%
2) 5%
3) 12%
4) 11%
5) 12.5%
6) 6%
7) 8%
8) 7%
9) 10%
10) None of these

Solution

Let the original price be Rs. 100.

New final price = 120 % of (75 % of Rs. 100) = Rs. [(120/100) * (75/100) * 100] = Rs. 90.

Decrease = 10%

Correct Option: 9 Best Solution (6)

11 Sep 2020 Arithmetic

Aflatoon, on his death bed, keeps half his property for this wife and divides the rest equally among his three sons : Ved, Charl and Dev. Some years later, Ved dies leaving half his property to his widow and half to his brothers Charl and Dev together, sharing equally. When Charl makes his will, he keeps half his property for his widow and the rest he bequeaths to his younger brother Dev. When Dev dies some years later, he keeps half his property for his widow and the remaining for his mother. The mother now has Rs. 1,827,000.What was the worth of the total property?

OPtion

1) 2480000
2) 2400000
3) 2460000
4) 2490000
5) 2784000
6) 2784800
7) 2784600
8) 2784200
9) 2784400
10) None of these

Solution

Let the total property of the Aflatoon be Rs.x.

After Aflatoon’s death, money possessed by the family members would be

Wife = x/2, Ved = x/6, Charl =x/6, Dev =x/6

After Ved’s death, money possessed by each of them would be

Aflatoon’s wife = x/2, Ved = 0,Ved’s wife = x/6, Charl = x/6 + x/24 = 5x/24, Dev = x/6 + x/24 = 5x/24

After Charl’s death, money possessed by them

Aflatoon’s wife has x/2, Ved has 0, Ved’s wife has x/12, Charl has 0, Charl’s wife has 5x/48, Dev has

5x/24 + 5x/48 = 15x/48

After Dev’s death, money possessed by them is:

Aflatoon’s wife has x/2 + 15x/96 = 63x/96, Ved has 0, Ved’s wife has x/12, Charl’s has 0, Charl’s wife has

5x/48, Dev has 0 and Dev’s wife has 15x/96

Now, given that 63x/96 = 1827000

x= 2784000

Correct Option: 5 Best Solution (4)