M4maths Previous Puzzles

16 Feb 2012 sum

30+31+32+33+................ upto x numbers > 12250
then minimum value of x will be

OPtion

1) 122
2) 123
3) 125
4) 128
5) 130
6) 132
7) 135
8) 134
9) 138
10) none of these

Solution

Formula for sum of x terms of an arithmetic progression is
S = (x/2)[(x-1)*2nd term - (x-3)*1st term]
= (x/2)[(x-1)*31 - (x-3)*30]
= x*(x+59)/2
so according to the given condition x*(x+59)/2 > 12250
so the minimum possible value of x = 130

Correct Option: 5 Best Solution (15)

15 Feb 2012 x

for 3^[(x-1)/x] > 2
least possible value of x out of these 10 options will be

OPtion

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

Solution

This statement is true for the options 4,5,6,7,8,9 and 10. But out of these 4th option which is 3 is least

Correct Option: 4 Best Solution (15)

14 Feb 2012 sum

In the sum of four 2-digit numbers, we got 27 more than the true result. This was due to the mistake of reversing the 2 digits of a number out of these four numbers. How many possibilities are there for the number which was printed wrongly

OPtion

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

Solution

possibilities are 14, 25, 36, 47, 58, 69

Correct Option: 5 Best Solution (7)

13 Feb 2012 sequence

0, 3, 22, 93, ..........
next number will be

OPtion

1) 134
2) 167
3) 190
4) 201
5) 234
6) 276
7) 297
8) 304
9) 404
10) none of these

Solution

this sequence is based on x + x^2 + x^4
here x = 0, 1, 2, 3, 4

Correct Option: 6 Best Solution (10)

10 Feb 2012 wheat

The cost of 3 types of wheat are 10 rupee, 14 rupee and 16 rupee. What will be the rate of a mixture of 20 Kg, 50 Kg and 40 Kg wheat of these 3 types respectively.

OPtion

1) 10
2) 11
3) 12
4) 13
5) 14
6) 15
7) 16
8) 17
9) 18
10) none of these

Solution

total cost = 10*20 + 14*50 + 16*40 = 1540
total wheat = 110 Kg
so average cost = 1540/110 = 14

Correct Option: 5 Best Solution (17)

09 Feb 2012 minimum

k+x = 10,
x+y+z >= 8
if y >= 3.5 and 0 <= z <= 4.2
all the 4 are positive real numbers
then maximum value of k will be

OPtion

1) 4.8
2) 5.3
3) 5.5
4) 6.7
5) 7.7
6) 9.7
7) 8.8
8) 3.5
9) 4.2
10) none of these

Solution

according to the given conditions y + z + 2 >= k
so maximum = 3.5 + 0 + 2 = 5.5

Correct Option: 3 Best Solution (0)

08 Feb 2012 a^3+b^2+c

32, 75, 144, 245, .....
next number will be

OPtion

1) 384
2) 414
3) 299
4) 305
5) 315
6) 404
7) 502
8) 510
9) 343
10) none of these

Solution

1+2^2+3^3 = 32
2+3^2+4^3 = 75
3+4^2+5^3 = 144
4+5^2+6^3 = 245
5+6^2+7^3 = 384

Correct Option: 1 Best Solution (0)

07 Feb 2012 result

A student got 67% marks. On eliminating the marks of Hindi and English, his % was 76 and on eliminating the marks of Hindi and Maths, his % was 65. What is the least possible marks in Hindi. Total subjects are 5 and total marks of each subject is 100.

OPtion

1) 40
2) 38
3) 43
4) 54
5) 49
6) 65
7) 30
8) 32
9) data are insufficient
10) none of these

Solution

According to the given condition
H + M + P + C + E = 335
M + P + C = 228
E + P + C = 195
so H + E = 107
and H + M = 140
so least possible marks in HINDI = 40

Correct Option: 1 Best Solution (7)

06 Feb 2012 dictionary

Rank of the word SUBJECT in the dictionary of words formed by using the letters of the word SUBJECT

OPtion

1) 3493
2) 3494
3) 3495
4) 3496
5) 3497
6) 3498
7) 3499
8) 3500
9) 3501
10) none of these

Solution

total no of words = 5040
so rank of SUBJECT = (5040/7)*4+(720/6)*5+(120/5)*0+(24/4)*2+(6/3)*1+(2/2)*1 = 2880+600+0+12+2+1 = 3495

Correct Option: 3 Best Solution (13)

04 Feb 2012 What will be the next number?

2, 5, 28, 257, ?

OPtion

1) 326
2) 524
3) 543
4) 645
5) 756
6) 1025
7) 2258
8) 3126
9) 4534
10) none of these

Solution

1+1, 2^2+1, 3^3+1, 4^4+1, 5^5+1
= 3126

Correct Option: 8 Best Solution (17)