M4maths Previous Puzzles

01 Aug 2019 Probability

If two letters are randomly taken one after the other from the word AUGUST, what is the probability that none of the letters would be vowels?

OPtion

1) 1/6
2) 2/7
3) 4/5
4) 1/5
5) 2/5
6) 3/11
7) 2/9
8) 3/13
9) 4/11
10) None of these

Solution

Number of vowels in AUGUST = 3
Number of consonants in AUGUST = 3
Total number of alphabets in AUGUST = 6

P(first letter is not vowel) = 3/6

P(second letter is not vowel) = 2/5

So, probability that none of letters would be vowels is = (3/6) × (2/5) = 1/5

Correct Option: 4 Best Solution (7)

31 Jul 2019 Age

Advika's age is 1/6th of her father's age. Advika's father's age will be twice Rahul's age after 10 years. If Rahul's eleventh birthdays was celebrated two years before, then what is Advika's present age.

OPtion

1) 8 years
2) 12 years
3) 11 years
4) 5 years
5) 6 years
6) 9 years
7) 10 years
8) 4 years
9) 7 years
10) None of these

Solution

Let Advika's present age = x

Then, her father's age = 6x


Given that Advika's father's age will be twice Rahul's age after 10 years.


Therefore, Rahul's age after 10 years = (1/2) * (6x + 10) = 3x + 5


Also given that Rahul's eleventh birthday was celebrated two years before. So Rahu;s present age = 11+2
Therefore, Rahul's age after 10 years = 11 + 2 + 10 = 23

3x+5 = 23
=> x = 6

Therefore, Advika's present age = 6 years

Correct Option: 5 Best Solution (2)

30 Jul 2019 Series

What is the nineth term of following series:
17, 19, 23,
29, 31,

OPtion

1) 41
2) 34
3) 37
4) 33
5) 39
6) 38
7) 43
8) 42
9) 47
10) None of these

Solution

Series is formed by prime number starting at 17:
17, 19, 23, 29, 31, 37, 41, 43, 47
so nineth term is 47
Option 9)

Correct Option: 9 Best Solution (0)

29 Jul 2019 Profit and Loss

A wholesaler allows a discount of 25 % on the list price to the retailer. The retailer sells at 5% below the list price. If the customer pays Rs.38 for an article what profit is made by the retailer on it?

OPtion

1) 10
2) 12
3) 18
4) 6
5) 3
6) 4
7) 8
8) 11
9) 13
10) None of these

Solution

If wholesaler's list price=100%, Retailer's CP=75% & SP=95%
If SP of 95% of the retailer costs Rs.38 to customer,so its CP of 75% will cost 75*38/95= 30
Profit is made by the retailer= 38 - 30 = 8

Correct Option: 7 Best Solution (5)

26 Jul 2019 LCM and HCF

The L.C.M of two numbers is 19500 and their H.C.F is 5. If one number is 260 the other is

OPtion

1) 315
2) 325
3) 375
4) 155
5) 255
6) 225
7) 275
8) 285
9) 305
10) None of these

Solution

hcf * lcm = product of two numbers
19500 * 5 = 260 * y
y = 375

Correct Option: 3 Best Solution (0)

25 Jul 2019 Percentage

If 30% of a = b, then b% of 30 is the same as:

OPtion

1) 3% of b%
2) 9% of b%
3) 0.9% of b%
4) 0.3% of b%
5) 27% of b%
6) 9% of a%
7) 18% of b%
8) 3% of a%
9) 13% of b%
10) None of these

Solution

30% of a = b
⇒ b = 3a/10

b% of 30 = (3a/10)30/100 = 9a/100 = 9% of a

Correct Option: 6 Best Solution (3)

24 Jul 2019 Distance Traveled

Pappu and Gappu are 180 km apart they start to move towards each other simultaneously, Pappu at speed 20 km/hr and Gappu at 10 km/hr if every hour they double their speed what is distance that Pappu will travel until he meets Gappu

OPtion

1) 64
2) 60
3) 75
4) 80
5) 100
6) 110
7) 130
8) 120
9) 140
10) None of these

Solution

In 2 hours Pappu covers (20+40) = 60 km
Gappu covers( 10 + 20) = 30 km,
Total covered = 90

In the next hour they have to cover (180 - 90) kms with the speeds 80km/hr and 40 km/hr respectively.

Let them take another t hrs to meet
so sum of the distance to be covered by both is 90 km
(80*t) + (40*t) = 90km
=> t= (3/4) hrs
we need to find out the distance covered by Pappu
which equals to = 60 + (80*(3/4)) = 120 km

Correct Option: 8 Best Solution (0)

23 Jul 2019 Simple Interest

A sum of Rs. 12,500 amounts to Rs. 25,000 in 10 years at the rate of simple interest. What is the rate of interest?

OPtion

1) 8
2) 12
3) 11
4) 6
5) 10
6) 18
7) 20
8) 9
9) 7
10) None of these

Solution

SI = 25000 - 12500 = 12500

SI = PRT/100

So R = 12500*100/(12500*10) = 10%

Correct Option: 5 Best Solution (0)

22 Jul 2019 Fraction

If a/b = 51/54 , c/d = 440/493, b/c = 29/32, e/f = 493/608 and d/e = 38/55 then what is the value of (abc/def)*17 ?

OPtion

1) 1005/188
2) 522/144
3) 261/72
4) 131/36
5) 1045/188
6) 104/29
7) 101/27
8) 145/28
9) 1045/288
10) None of these

Solution

a/d = (a/b)*(b/c)*(c/d) = 55/72
b/e = (b/c)*(c/d)*(d/e) = 19/34
c/f = (c/d)*(d/e)*(e/f) = 1/2

So 17*abc/def = 17*(a/d)*(b/e)*(c/f) = 17*(55/72) * (19/34) * (1/2) = 55*19*1/288 = 1045/288

Option 9)

Correct Option: 9 Best Solution (2)

19 Jul 2019 Simple Interest

Vijay took a loan of Rs. 10976 with simple interest for as many years as the rate of interest. If he paid Rs.686 as interest at the end of the loan period, what was the rate of interest?

OPtion

1) 4%
2) 3.5%
3) 2.5%
4) 6.25%
5) 16%
6) 1.5%
7) 8%
8) 1.75%
9) 1.16%
10) None of these

Solution

SI = PRT/100

R = T = x

So 686 = 10976*x^2/100

=> x^2 = 6.25
=> x = 2.5

Correct Option: 3 Best Solution (4)