M4maths Previous Puzzles

08 Jul 2011 tape and tank

There are 3 tapes in a tank, 2 for filling water and 1 for drain. The first 2 tapes can fill the tank alone in 10 and 12 hours respectively, whereas 8 hours are required to drain all the water by third tape alone.
If we open all the 3 tapes, then hours required to fill the tank completely are

OPtion

1) 6
2) 100/9
3) 7
4) 13/2
5) 5
6) 120/7
7) 92/5
8) 100/13
9) 130/9
10) none of these

Solution

total tank filled in 1 hour = (1/10)+(1/12)-(1/8) = 7/120
so hours required to fill the complete tank = 120/7

Correct Option: 6 Best Solution (0)

07 Jul 2011 powers of 3

50*49*48*47*..................*4*3*2*1 = x*(3^n) where x is an integer not divisible by 3 then integral value of n will be

OPtion

1) 16
2) 17
3) 21
4) 22
5) 25
6) 48
7) 50
8) 15
9) data are insufficient
10) none of these

Solution

Formula for solving the question is
[50/3] + [50/9] + [50/27], here [] represents integral value
= 16 + 5 + 1
= 22

Correct Option: 4 Best Solution (6)

06 Jul 2011 scheme

The cost rupee per Kg. of potato, onion, tomato, garlic and ginger are respectively 9, 14, 18, 43 and 35. There are 5 schemes of a shopkeeper, which 1 is relatively most profitable.
n. Potato Onion Tomato Garlic Ginger
1 2 kg 1 kg 1 kg 1/2 kg 100 gm free
2 4 kg 2 kg 1/2 kg 200 gm free 1/2 kg
3 1 kg free 4 kg 1 kg 1/2 kg 1/2 kg
4 4 kg 1 kg free 2 kg 1 kg 1/2 kg
5 6 kg 4 kg 1 kg free 1 kg 1/2 kg

OPtion

1) 1
2) 2
3) 3
4) 4
5) 5

Solution

Bill 1 total purchasing = 71.5 and discount = 3.5 so 3.5/71.5 = 0.048951
Bill 2 total purchasing = 90.5 and discount = 8.6 so 8.6/90.5 = 0.095028
Bill 3 total purchasing = 113 and discount = 9.0 so 9.0/113.0 = 0.079646
Bill 4 total purchasing = 132.5 and discount = 14 so 14/132.5 = 0.105660
Bill 5 total purchasing = 170.5 and discount = 18 so 18/170.5 = 0.105572

Correct Option: 4 Best Solution (1)

05 Jul 2011 vodafone

What will be the rank of VODAFONE in the dictionary formed by the letters of the word VODAFONE

OPtion

1) 19568
2) 20423
3) 17934
4) 20134
5) 19572
6) 16547
7) 12346
8) 18459
9) data are insufficient
10) none of these

Solution

On arranging letters in order we get
A, D, E, F, N, O, O, V
now make attention on the trick
total possible words = 8*7*6*5*4*3*2*1/2*1 = 20160
so rank = 2520*7 + 360*5 + 120*1 + 24*0 + 6*1 + 2*2 + 1*1 + 1 = 19572
here 2520 is 20160/8 and 7 is the no. of letters before V
360 is 2520/7 and 5 is the no. of letters before O
now O comes twice in the word so
total words for the next step = 360*2
120 is 720/6 and 1 is the no. of letters before D
24 is 120/5 and 0 is the no. of letters before A
6 is 24/4 and 1 is the no. of letters before F
2 is 6/3 and 2 is the no. of letters before O
1 is 2/2 and 1 is the no. of letter before N
Last 1 is necessary to add

Correct Option: 5 Best Solution (0)

04 Jul 2011 number

What will be the next number of the sequence
6, 96, 24576, 100663296, ......

OPtion

1) 6597069766656
2) 4678453212344
3) 4509003458678
4) 5640079685442
5) 7695043950568
6) 9823145006978
7) 1200239495866
8) 6957980023952
9) Data are wrong
10) none of these

Solution

The given sequence is
6
6*16 = 96
96*16*16= 24576
24576*16*16*16 = 100663296
100663296*16*16*16*16 = 6597069766656

Correct Option: 1 Best Solution (8)

02 Jul 2011 next number

next number of the sequence 7, 13, 10, 7, 22, ..... will be

OPtion

1) 21
2) 24
3) 25
4) 28
5) 32
6) 49
7) 43
8) 45
9) 54
10) none of these

Solution

the power sequence of 7 is 7, 49, 343, 2401, 16807, 117649
on adding the digits of the numbers we get a sequence
7, 13, 10, 7, 22, 28
so 28 will be the answer.

Correct Option: 4 Best Solution (0)

01 Jul 2011 k

k:[(k^2)-1]]::6:5, so k will be (It is given that k is a positive number)

OPtion

1) 0.5
2) 1.0
3) 1.5
4) 2.0
5) 2.5
6) 3.0
7) 3.5
8) 4.0
9) 4.5
10) none of these

Solution

k/[(k^2)-1] = 6/5
implies k/[(k^2)-1] = 1.5/1.25
implies k/[(k^2)-1] = 1.5/(2.25-1)
implies k/[(k^2)-1] = 1.5/(1.5^2-1)
so k = 1.5

Correct Option: 3 Best Solution (14)

30 Jun 2011 marks

Ram got 98 % marks. Shyam got 1 % marks less than Ram. How much more % marks Ram got w. r. t. marks of Shyam.

OPtion

1) 1.431
2) 1.031
3) 1.231
4) 1.098
5) 2.444
6) 2.076
7) 2.098
8) 2.043
9) 3.111
10) none of these

Solution

Marks of Ram = 98 %
so that of Shyam will be 98-1 = 97%
now we have to find the % of difference of marks w. r. t. marks of Shyam it will be 1*100/97 = 100/97 = 1.031

Correct Option: 2 Best Solution (4)

29 Jun 2011 solve

99^3-56^3-43^3-3*99*56*43=

OPtion

1) 54658
2) 45368
3) 65438
4) 23145
5) 78654
6) 12321
7) 23190
8) 18769
9) 22314
10) none of these

Solution

According to formula we know that
a^3+b^3+c^3-3*a*b*c = (a+b+c)(a^2+b^2+c^2-a*b-b*c-c*a)
Here a=99, b=-56, c=-43
so a+b+c = 99-56-43 = 0
hence answer will be 0
so option 10th is correct

Correct Option: 10 Best Solution (11)

28 Jun 2011 cost

What will be the cost of 49 Kg ginger at a rate of 49 rupee per Kg it there is a discount of 49% in this purchase.

OPtion

1) 1000
2) 1120.5
3) 1195.5
4) 1224.5
5) 1328
6) 1526.5
7) 1656.5
8) 1770
9) 1800
10) none of these

Solution

[(49*49)*(100-49)]/100 = 1224.5

Correct Option: 4 Best Solution (10)