M4maths Previous Puzzles

24 Dec 2009 how may number plates are possible?

A car plate is written by taking 3 alphabets and 3 integers, if after 3 alphabets 3 zeros are not allowed,
then total possible car plates with no code repeated are ?

OPtion

1) 11232000
2) 17576000
3) 17576
4) 17593576
5) 17558424
6) 14236560
7) 15600000
8) 17568424
9) 12812904
10) 15818400

Solution

total alphabets are 26 hence total possibilities for taking 3 alphabets are 26*26*26 = 17576
Total integers are 10 hence total possibilities for taking 3 integers are
10*10*10 = 1000
Total number of avoided cases are 26*26*26*1*1*1 = 17576
Therefore answer is 17576 * 1000 – 17576 = 17558424

Correct Option: 5 Best Solution (0)

23 Dec 2009 electricity bill

1000 watt per hour consumption of electricity is known as 1 unit and cost of 1 unit electricity is Rs 2.15. Mr Gupta has the following electrical apparatus in his home-
No. Apparatus Power Hours of utilization
1. 2 electricity bulb 100 watt 2 Hrs. 12 min per day
2. 4 tube light 40 watt 6 Hrs. 6 min per day
3. 1 room heater 1000 watt 3 Hrs. 42 min per day
4. 1 television 60 watt 2 Hrs. 30 min per day
5. 1 computer 100 watt 1 Hrs. 36 min per day
6. 1 washing machine 100 watt 3 Hrs. 30 min per week
The bill of electricity of Mr Gupta in a month of 30 days is

OPtion

1) 288
2) 348
3) 422
4) 402
5) 325
6) 353
7) 417
8) 421
9) 298
10) 279

Solution

Watt-Hour per day
for bulbs = 2*100*2.2 = 440
for tubes = 4*40*6.1 = 976
for heater = 1*1000*3.7 = 3700
for television = 1*60*2.5 = 150
for computer = 1*100*1.6 = 160
for machine = 1*100*3.5/7 = 50
Total Watt Hour per day for all the apparatus = 5476
Monthly Watt Hour consumed = 5476*30 = 164280 Kilowatt consumed = 164.28
Total Bill of consumption = 164.28*2.15 = 353.202 = 353 approx

Correct Option: 6 Best Solution (0)

22 Dec 2009 Multiply 2 numbers

82?6 x 4?53 = ??3?5???
If both the blank space (?) in left hand side are filled by the same integer from 0 to 9, then ? is

OPtion

1) 0
2) 1
3) 2
4) 3
5) 4
6) 5
7) 6
8) 7
9) 8
10) 9

Solution

check all the possible cases.


8276 x 4753 = 39335828

Correct Option: 8 Best Solution (0)

21 Dec 2009 Sum of series

2000+1000+500+250+125+62.5+.......up to infinite

OPtion

1) 5000
2) 4500
3) 4001
4) 4000
5) 3999
6) infinite
7) 6000
8) 5001
9) 4999
10) 10000

Solution

Correct Option: 4 Best Solution (2)

18 Dec 2009 Power of 4

Three numbers are formed by taking three successive powers of 4. The sum of these three numbers is 21504.
What is the greatest power raised

OPtion

1) 10
2) 8
3) 9
4) 6
5) 5
6) 4
7) 7
8) 11
9) 12
10) 13

Solution

4^x + 4^(x+1) + 4^(x+2) = 21504
=> 4^x (1+4+4^2) = 21504
=> 4^x = 21504/21
=> 4^x = 1024
=> x = 5
Hence greatest power is 7

Correct Option: 7 Best Solution (5)

17 Dec 2009 fill blank with mathematical operations

23 .... 8 .... 0.54 .... 2 .... 12 = 13.795
Fill all the blank spaces by mathematical operations

OPtion

1) + x / -
2) / + - x
3) - x / +
4) / x + -
5) - + x /
6) x / + -
7) - + / x
8) x / - +
9) / - x +
10) + / x -

Solution

23 / 8 - 0.54 x 2 + 12 = 13.795

Correct Option: 9 Best Solution (1)

16 Dec 2009 coded number

Some numbers and their codes are given below
Number Code
475 4
493 0
694 7
862 1
Then code for 524 is

OPtion

1) 7
2) 4
3) 5
4) 6
5) 3
6) 8
7) 9
8) 0
9) 1
10) 2

Solution

if we consider 475 as number of months then on dividing by 12, we get 39 (years) as quotient and
7 (months) as reminder, on dividing 39 by 7, reminder is obtained as 4, hence the code is formed as 4.
Similarly for others.

Correct Option: 5 Best Solution (0)

15 Dec 2009 Age in Decimal

The age of a man is thirty five years and seven and half a month. What is its age in decimal representation?

OPtion

1) 35.72
2) 35.75
3) 35.5
4) 35.71
5) 35.712
6) 35.625
7) 35.705
8) 35.075
9) 35.621
10) 35.6005

Solution

seven and half a month = 7.5/12 years = 0.625 years
hence the age is 35.625 years

Correct Option: 6 Best Solution (13)

14 Dec 2009 find the value of Y

If y = (6+x)^2/(6-x)^2 is not a perfect square integer and x is less than 6 and greater than 0; then the value of y is

OPtion

1) 100/9
2) 16/3
3) 81/8
4) 49/25
5) 20
6) 1/2
7) 121
8) 25
9) 25/16
10) 24

Solution

On taking x = 1, 2, 3, 4, 5 respectively, we get
y = 49/25, 4, 9, 25, 121
Only 49/25 is not a perfect square integer, hence is the solution.

Correct Option: 4 Best Solution (10)

11 Dec 2009 decode the word

Four numbers and their codes are given below
Number Code
4725 76
6423 64
8142 29
4820 16
Then code for 5332 is

OPtion

1) 58
2) 82
3) 76
4) 71
5) 93
6) 99
7) 64
8) 87
9) 43
10) 37

Solution

First number is 4725
On dividing 47 by 25, we get 1 as quotient and 22 as reminder
On dividing 25 by 22, we get 1 as quotient and 3 as reminder
On dividing 47 by 3, we get 15 as quotient and 2 as reminder
On dividing 25 by 2, we get 12 as quotient and 1 as reminder
On dividing 47 by 1, we get 47 as quotient and 0 as reminder
Now adding all the quotient we get 1+1+15+12+47 = 76
Take similar steps for finding the other codes.
Remember that you have to proceed upto the step where 0 is obtained as reminder.

Correct Option: 8 Best Solution (0)