M4maths Previous Puzzles

24 May 2012 code

If ACT - ANT = 11
then WISE - RISE = ?

OPtion

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

Solution

ACT - ANT
in this expression only C and N are different so N-C = 14-3 = 11
similarly in second R-W = 18-23 = -5

Correct Option: 3 Best Solution (0)

23 May 2012 find number

The sum of a positive number and its reciprocal number (for example x and 1/x) is (2n+1)/6 where n is any integer ranging from 1 to 6. Then the number x will be (out of the 10 options given)

OPtion

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

Solution

x + (1/x) = (x^2+1)/x
and we know that x^2+1>2x
so (x^2+1)/x>2
if we take n = 1,2,3,4,5,6 in (2n+1)/6 then for only 6, it will be greater than 2
so definitely n=6
so eq. will become x+(1/x)=13/6
by solving this eq. we will get x = 3/2 and 2/3
but 2/3 is not in the options so answer will be 3/2 out of the 10 given answers

Correct Option: 6 Best Solution (13)

22 May 2012 coin

If we have 1, 2, 5, 10, 20 and 50 rupee coins then for getting the sum equal to any of the value from 1 rupee to 100 rupee , minimum no. of coins required will be

OPtion

1) 6
2) 7
3) 8
4) 10
5) 12
6) 20
7) 50
8) 80
9) 100
10) none of these

Solution

If we have 1 rupee, 2 rupee, 2 rupee, 5 rupee, 10 rupee, 20 rupee, 20 rupee and 50 rupee then we can obtain any value from 1 rupee to 100 rupee

Correct Option: 3 Best Solution (9)

21 May 2012 sequence

5, 20, 45, 80, 125, .................
next number of the sequence will be

OPtion

1) 130
2) 150
3) 160
4) 180
5) 210
6) 240
7) 270
8) 290
9) 300
10) none of these

Solution

5 = 5*(1^2)
20 = 5*(2^2)
45 = 5*(3^2)
80 = 5*(4^2)
125 = 5*(5^2)
next = 5*(6^2) = 180

Correct Option: 4 Best Solution (43)

18 May 2012 performance percentage

Below written is the list of cost and rating percentage (on some basis) of a number of appliance. On this basis the most effective appliance with minimal cost will be
Appliance Cost Rating percentage
cooler 6500 25
refrigerator 9500 15
air conditioner 23500 20
tube light 450 2
iron 650 3
mixer and juicer 3500 8
television 15500 12
computer 28500 20
washing machine 18500 10
table fan 1350 5

OPtion

1) cooler
2) refrigerator
3) air conditioner
4) tube light
5) iron
6) mixer and juicer
7) television
8) computer
9) washing machine
10) table fan

Solution

cost list for 100% performance will be
appliance cost for 100% performance
1) cooler 6500*100/25 = 26000
2) refrigerator = 63334 approx
3) air conditioner = 117500
4) tube light = 22500
5) iron = 21667 approx
6) mixer and juicer = 43750
7) television = 129167 approx
8) computer = 142500
9) washing machine = 185000
10) table fan = 27000

Correct Option: 5 Best Solution (0)

17 May 2012 minimum value

minimum value of x^2+4x+1 will be

OPtion

1) -4
2) -3
3) -2
4) -1
5) 0
6) 1
7) 2
8) 3
9) 4
10) none of these

Solution

x^2+4x+1 = x^2+4x+4-4+1 = (x+2)^2-3
so minimum value of the expression will be -3

Correct Option: 2 Best Solution (0)

16 May 2012 zero

How many zeros are there in the product
200*199*198*197..................*4*3*2*1

OPtion

1) 43
2) 44
3) 45
4) 46
5) 47
6) 48
7) 49
8) 50
9) 54
10) none of these

Solution

200/5 = 40 zeros because every 5 will make a zero in the product
40/5 = 8
8/5 = 1.6
so total zeros = 40+8+1 = 49

Correct Option: 7 Best Solution (6)

15 May 2012 dictionary

rank of the word HORSE in the dictionary formed by the letters of the word HORSE

OPtion

1) 25
2) 26
3) 28
4) 32
5) 34
6) 36
7) 38
8) 40
9) 45
10) none of these

Solution

Total number of words = 5*4*3*2*1 = 120
now increasing sequence of letters of the word HORSE is E, H, O, R, S
so rank of HORSE = (120/5)*(2-1)+(24/4)*(2-1)+(6/3)*(2-1)+(2/2)*(2-1)+1
= 24+6+2+1+1 = 34

Correct Option: 5 Best Solution (11)

14 May 2012 series

1+4+18+43+79+..............
next number of the series will be

OPtion

1) 102
2) 109
3) 112
4) 116
5) 119
6) 121
7) 123
8) 126
9) 136
10) none of these

Solution

4 - 1 = 3
18 - 4 = 14
43 - 18 = 25
79 - 43 = 36
the difference of all the differences = 11
so next difference = 36+11 = 47
so next number = 79+47 = 126

Correct Option: 8 Best Solution (0)

11 May 2012 solve

x+10y = 17 and x+y = 8
so 16x+15y will be

OPtion

1) 127
2) 124
3) 115
4) 112
5) 109
6) 108
7) 105
8) 98
9) 92
10) none of these

Solution

x+10y = 17 and x+y = 8
on solving we will get x = 7 and y = 1

Correct Option: 1 Best Solution (30)