M4maths Previous Puzzles

14 Feb 2013 Linear Equation

Mukesh has x dollars more than the amount Mohan has and together they have a total of y dollars. Which of the following represents the number of dollars that Mohan has?

OPtion

1) (y-x)/2
2) y-(x/2)
3) (y/2)-x
4) 2y-x
5) 2x-y
6) y-x
7) 2y/x
8) 2x/y
9) x+y
10) None of these

Solution

let mohan has P dollar
then Mukesh has p+x dollar
by the condition
p+x+p=y
2p+x=y
2p=y-x
p=(y-x)/2

Correct Option: 1 Best Solution (19)

13 Feb 2013 geometry

In a trapezium sum of a pair of opposite angles (A and B) is 180 degree. If one other angle (C) is half the remaining angle (D). Then difference of C and D is

OPtion

1) 45
2) 30
3) 15
4) 60
5) 75
6) 90
7) 120
8) 135
9) 35
10) none of these

Solution

let C = x so D = 2x
x+2x = 180
so x = 60 and 2x = 120
so difference = 120-60 = 60

Correct Option: 4 Best Solution (14)

12 Feb 2013 Age Problem

If fathers age is thrice his sons age and mothers age is 5 less than her husbands age then the difference between mothers and sons age will be. The age of son is x.

OPtion

1) 2x-5
2) 3x-5
3) (x/2)-5
4) x-5
5) 3x
6) 5x-5
7) 3x-3
8) 5x-25
9) 3x
10) None of these

Solution

age of son is x
then fathers age 3x
mothers age 3x-5
mother - son (age)= 3x-5-x = 2x-5
option 1

Correct Option: 1 Best Solution (31)

11 Feb 2013 Next Numbers

What is the next no. of following sequence
1,3,6,11,18,29,42....

OPtion

1) 38
2) 47
3) 59
4) 57
5) 63
6) 67
7) 73
8) 78
9) 82
10) None of these

Solution

The difference between numbers is
3-1 = 2
6-3 = 3
11-6 = 5
18-11 = 7
29- 18 = 11
42- 29 = 13

so the difference for next number will be 17

42 + 17 = 59
option 3

Correct Option: 3 Best Solution (5)

09 Feb 2013 arithmetic

The L.C.M. and H.C.F. of 3 integers are same. Out of these options, sum of these integers will be

OPtion

1) 32
2) 28
3) 49
4) 62
5) 98
6) 100
7) 44
8) 87
9) data are insufficient
10) none of these

Solution

87 is divisible by 3 so all integers are 29.
Without making these integers equal L.C.M. and H.C.F. will not be equal.

Correct Option: 8 Best Solution (8)

08 Feb 2013 square

On increasing the length of any square by 2 unit and decreasing the breadth by 2 unit, the new area will be

OPtion

1) 12 unit more
2) 12 unit less
3) 8 unit more
4) 8 unit less
5) 4 unit more
6) 4 unit less
7) 2 unit more
8) 2 unit less
9) no change
10) none of these

Solution

let the side is x so area = x^2
area of rectangle = (x+2)(x-2)
so difference = 4 unit (less)
It does not matter what the value of x is

Correct Option: 6 Best Solution (0)

07 Feb 2013 equation

if x + 1/x = 4
then how many integers are there between the roots of this equation.

OPtion

1) 0
2) 1
3) 2
4) 3
5) 4
6) 5
7) 6
8) 7
9) no real roots so nothing can be said
10) none of these

Solution

on solving roots are .268 and 3.732
so answer = 3
second method
on putting x=0 value of expression = 1
x=1 = -2
x=3 = -2
x=4 = 1
so 1, 2 and 3 are possible answers

Correct Option: 4 Best Solution (10)

05 Feb 2013 integers

for 3 non negative integers x, y and z
x+2y+3z = 6
possible no. of outcomes are

OPtion

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

Solution

0,0,2
0,3,0
1,1,1
2,2,0
3,0,1
4,1,0
6,0,0

Correct Option: 7 Best Solution (0)

04 Feb 2013 What will be the next number

4, 9, 6, 5, 6, 9, ?

OPtion

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

Solution

after square a number just take it last digit.
2 -> 4
3 -> 9
4 -> 1 6
5 -> 2 5
6 -> 3 6
7 -> 7 9
8 -> 6 8

Correct Option: 4 Best Solution (6)

03 Feb 2013 Dictionary Word

Rank of the word DAVID in the dictionary of words formed by letters of the word DAVID will be.

OPtion

1) 10
2) 12
3) 15
4) 17
5) 18
6) 22
7) 24
8) 27
9) 30
10) None of these

Solution

(60/5)*1+((12*2)/4)*0+(6/3)*2+(2/2)*1+1
= 12 + 0 + 4 + 1 + 1
= 18

Correct Option: 5 Best Solution (0)