M4maths Previous Puzzles

16 Sep 2021 Simplification

What approximate value will come in place of
the question mark (?) in the following question?
1141.99 + ? – 1035.01 = 1471. 98 – 1020.01

OPtion

1. 165
2. 345
3. 321
4. 308
5. 342
6. 402
7. 408
8. 378
9. 398
10. None of the above

Solution

1141.99 + ? – 1035.01 = 1471. 98 – 1020.01
1142 + ? – 1035 = 1472 – 1020
107 + ? = 452
? = 452 – 107
? = 345

Correct Option: 2 Best Solution (4)

15 Sep 2021 CABIN

How many words can be formed by using all letters of the word 'CABIN'?

OPtion

1. 720
2. 24
3. 120
4. 60
5. 65
6. 75
7. 88
8. 115
9. 36
10. None

Solution

The word 'CABIN' has 5 letters and all these 5 letters are different.
Total number of words that can be formed by using all these 5 letters
= 5P5
= 5!
= 5×4×3×2×1
= 120

Correct Option: 3 Best Solution (4)

14 Sep 2021 Population

The population of a town is 16200. It decreases annually at the rate of 40% p.a. What was its population 3 years ago?

OPtion

1. 75000
2. 65000
3. 84900
4. 93600
5. 92363
6. 68655
7. 83365
8. 91190
9. 78875
10. None of the above

Solution

(Ago = 100 numerator)
Ago 3 years = 16200×(100/60×100/60×100/60)
= 75000

Correct Option: 1 Best Solution (3)

13 Sep 2021 Misreading

A number 168 was misread as 24. Find the reading error in per cent.

OPtion

1. 25.7
2. 42.8
3. 42.6
4. 85.7
5. 98.6
6. 83.9
7. 79.2
8. 72.6
9. 66.5
10. None of the above

Solution

Error = 168 – 24 = 144
Therefore, % error = 144/168
[Since, we know decrease% = decrease in value/original value × 100 %]
= 144/168 × 100 = 85.7 %

Correct Option: 4 Best Solution (4)

10 Sep 2021 Seconds

Total seconds between 2:10 AM to 3:25 PM will be

OPtion

1) 47700
2) 49000
3) 51200
4) 56900
5) 65000
6) 70000
7) 76500
8) 80000
9) 82600
10) None of the above

Solution

Total seconds between 2:10 AM to 2:10 PM = 86400/2 = 43200
total seconds between 2:10 PM to 3:25 PM = 3600 + 900 = 4500
so total seconds = 43200 + 4500 = 47700

Correct Option: 1 Best Solution (4)

09 Sep 2021 sequence

next number of the sequence 6, 13, 32, 69, 130, .......... will be

OPtion

1) 221
2) 242
3) 254
4) 261
5) 287
6) 299
7) 301
8) 339
9) 400
10) none of these

Solution

1^3+5=6,
2^3+5=13,
3^3+5=32,
4^3+5=69,
5^3+5=130,
6^3+5=221.

Correct Option: 1 Best Solution (2)

08 Sep 2021 PROBABILITY

There are 5 switches in a board. In these 5 switches 1 is attached with the fan. A person has to start the fan in 2 attempts only. Probability of success will be

OPtion

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

Solution

Probability of not succeeding in 1st attempt = 4/5
Probability of not succeeding in 2nd attempt = 3/4

Probability of not succeeding in 1st two attempts = (4/5)*(3/4) = 3/5

Probability of succeeding in 1st two attempts = 1-3/5=2/5

Correct Option: 2 Best Solution (0)

07 Sep 2021 integers

The average of 5 successive integers is 12.Their product will be

OPtion

1) 134560
2) 154680
3) 165490
4) 213460
5) 234240
6) 236580
7) 240240
8) 283450
9) 324340
10) none of these

Solution

Average of 5 successive integer=5x+4=60
Hence, numbers are 10,11,12,13,14
Their products are 10*11*12*13*14=240240

Correct Option: 7 Best Solution (5)

06 Sep 2021 Number Game

(2^3 + 3^4 + 4^5 + 5^6) - (6^5 + 5^4 + 4^3 + 3^2) = ?

OPtion

1) 7862
2) 8264
3) 8865
4) 16738
5) 8474
6) 5648
7) 9234
8) 7684
9) 6578
10) none of these

Solution

(2^3+3^4+4^5+5^6)=16738
(6^5+5^4+4^3+3^2)=8474
therefore (16738-8474)=8264

So the right option is 2)8264

Correct Option: 2 Best Solution (3)

03 Sep 2021 Difference

difference between sum of squares of 4,5,6 and their sum is?

OPtion

1) 57
2) 59
3) 60
4) 61
5) 62
6) 63
7) 64
8) 65
9) 66
10) None of the above

Solution

4^2+5^2+6^2=16+25+36
=77
4+5+6=15
Diff is =77-15
=62
So the Option 5

Correct Option: 5 Best Solution (5)