M4maths Previous Puzzles

26 May 2020 Time and Work

Pankhudi has a toaster with two slots that toasts one side of each piece of bread at a time, and it takes one minute to do so.

If she wants to make 3 pieces of toast, what is the least amount of time she needs to toast them on both sides?

OPtion

1) 2 minutes
2) 3 and half minutes
3) 4 minutes
4) 300 seconds
5) 2 and half minutes
6) 180 seconds
7) 240 seconds
8) 600 seconds
9) 5.5 minutes
10) None of these

Solution

3 minutes. She puts two pieces in the toaster, toasting one side of each. Then she flips one of them, takes one out, and puts the completely untoasted piece into the toaster. Finally, she takes out the toasted piece and puts the two half-toasted pieces of bread into the toaster for a minute and she's done.

Correct Option: 6 Best Solution (0)

25 May 2020 Eid Mubarak

Rank of the word EID in the dictionary of words formed by the letters of the word EID?

OPtion

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

Solution

2 + 1 + 0 + 1= 4
i.e., Rank of the word 'EID' = 4

Correct Option: 3 Best Solution (4)

22 May 2020 Ages

A is seven years older than B who is twice as old as C. The total of the ages of A, B and C is 87. How old is C?

OPtion

1) 37
2) 29
3) 39
4) 16
5) 32
6) 20
7) 18
8) 17
9) 15
10) None of these

Solution

A-B = 7
B/C = 2
B+7+B+B/2=87
Solving we get B= 32 and C=16

Correct Option: 4 Best Solution (4)

21 May 2020 Average

What is the average of all multiples of 17 lying between 430 and 530?

OPtion

1) 464.5
2) 498.5
3) 489.5
4) 484.5
5) 485.4
6) 486.5
7) 491.5
8) 490.5
9) 494.5
10) None of these

Solution

All such numbers are:
442
459
476
493
510
527

There sum = 2907
Avg. = 2907/6 = 484.5

Correct Option: 4 Best Solution (0)

20 May 2020 Compound Interest

There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of Rs. 12,000 after 4 years at the same rate?

OPtion

1) 17369.2
2) 17469.2
3) 17569.2
4) 17669.2
5) 17769.2
6) 5569.2
7) 3972
8) 3972.2
9) 5659.2
10) None of these

Solution

Let P = Rs. 100. Then, S.I. = Rs. 60 and T = 6 years.
R= 60*100/(100*6) = 10%

CI = 12000[ (1+ 10/100)^4 -1]
=> 5569.2

Correct Option: 6 Best Solution (3)

19 May 2020 Probability

An alphabet is randomly selected from the word HINDUSTAN
What is the probability that it would be a vowel?

OPtion

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

Solution

HINDUSTAN
Total character count = HINDUSTAN
Number of vowels = 3

Probability = 3/9 = 1/3

Correct Option: 1 Best Solution (3)

18 May 2020 Simple Interest

Find Rate, when Principal = $ 2020; Amount= $ 3838 and Time = 18 years.

OPtion

1) 10.56 %
2) 10.16 %
3) 10.26 %
4) 10.86 %
5) 10.96 %
6) 8
7) 7
8) 6
9) 5
10) None of these

Solution

SI = 3838 - 2020 = 1818
R = SI*100/(P*T) = 1818*100/(2020*18) = 5 %

Correct Option: 9 Best Solution (3)

15 May 2020 Series

Given the series:
0, 1, 1, 2, 3, 5, 8, 13, ...
What is the tenth term?

OPtion

1) 24
2) 25
3) 18
4) 21
5) 36
6) 33
7) 45
8) 34
9) 43
10) None of these

Solution

Its a Fibonacci series:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34

Correct Option: 8 Best Solution (0)

14 May 2020 Digits

When you reverse the digits of the number 14 the number increases by 27. What is the sum of all such two digit numbers which increase by 27 when their digits are reversed?

OPtion

1) 202
2) 220
3) 205
4) 200
5) 201
6) 203
7) 199
8) 198
9) 196
10) None of these

Solution

10x + y - (10y + x ) = 27
=> 9x-9y = 27
=> x - y = 3
Following numbers satisfy the criteria of x-y=3
14, 25, 36, 47, 58, 69
Their Sum = 14 +25 + 36 + 58 + 69 =249

Correct Option: 10 Best Solution (0)

13 May 2020 Profit & Loss

A shopkeeper has 2020 kgs of rice, part of which he sells at 1% loss and the rest at 7% profit. He gains 2% on the whole. What is the difference between the quantities of rice sold at 7% profit and that sold at 1% loss?

OPtion

1) 1215
2) 1015
3) 1515
4) 1625
5) 505
6) 1715
7) 1815
8) 515
9) 520
10) None of these

Solution

(Quantity of Cheaper)/(Quantity of Dearer) = (Price of Dearer - Mean Price)/(Mean Price - Price of Cheaper)

(Quantity of Cheaper)/(Quantity of Dearer) = (107 - 102)/(102-99) = 5/3

Total Quantity = 2020 KG

The quantity sold at 1% loss is = (5/8) * 2020 = 1262.5
The quantity sold at 2% profit is = (3/8) * 2020 = 757.5
Diff between quantities = 505

Correct Option: 5 Best Solution (1)