M4maths Previous Puzzles

23 Nov 2020 PROBABILITY

Tickets numbered 1 to 37 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 4 or 10?

OPtion

1. 11/37
2. 37/11
3. 12/37
4. 37/12
5. 11/12
6. 10/37
7. 37/10
8. 4/10
9. 10/4
10. None of the above

Solution

Here, S = {1, 2, 3, 4, ...., 36,37}.
Let E = event of getting a multiple of 4 or 10
= {4,8,12,16,20,24,28,32,36,10, 30}.
P(E) = n(E)/n(S) = 11/37

Correct Option: 1 Best Solution (2)

20 Nov 2020 AVERAGE

Average age of 6 Children’s of a family is 8 years. The average of Children’s and their parent’s age is 22 years. If father is 8 year older than the mother then find the age of their mother.

OPtion

1) 42
2) 48
3) 60
4) 50
5) 56
6) 45
7) 62
8) 58
9) 59
10) None of the above

Solution

Let, Mother’s age is = X
Then father’s age = X+8
Sum of age of 6 children’s = 48
Sum of children’s and their parents age = 48+X+X+8= 56+2X
Average of children’s and their parents age = 56+2X /8
As given, 22= 56+2X/8
2X = 120, X= 60 years

Correct Option: 3 Best Solution (2)

19 Nov 2020 Ratio

A Car covers distance 440 km in 8 hrs. A motorbike covers the same distance in 5 hrs. What is the respective ratio between the speed of the Car and the motorbike?

OPtion

1) 3:4
2) 1:2
3) 5:6
4) 6:7
5) 8:5
6) 5:8
7) 3:5
8) 3:8
9) 7:8
10) None of the above

Solution

Distance covered by Car = 440 Km
Time taken to cover 440 km = 08 Hrs.
Speed of Car = 440/8= 55 Km/Hrs.
Speed of motorbike = 440/5 = 88 Km/Hrs.
Hence the required ratio = 55: 88 = 5: 8

Correct Option: 6 Best Solution (3)

18 Nov 2020 Permutation

From an organization of 6 persons, in how many ways can we choose a manager and a senior manager assuming one person cannot hold more than one position?

OPtion

1) 56
2) 42
3) 28
4) 32
5) 36
6) 30
7) 34
8) 40
9) 50
10) None of the above

Solution

Total number of people in commit = 6
Number of positions to be filled = 2
Number of permutations = 6P2 = 6!/(6-2)! =6!/4! = 30

Correct Option: 6 Best Solution (2)

17 Nov 2020 PROBABILITY

A batsman hits a Six 8 times out of 40 balls he plays. Find the probability that he did not hit a six.

OPtion

1) 2/5
2) 3/5
3) 2/8
4) 2
5) 4/5
6) 5/4
7) 6/4
8) 5/2
9) 5/3
10) None of the above

Solution

Total number of balls = 40
Numbers of Six = 8
Number of time batsman didn’t hit six = 40 – 8 = 32
Probability he did not hit a six = 32/40 = 4/5

Correct Option: 5 Best Solution (3)

16 Nov 2020 ARITHMETIC PROGRESSIONS

Which term of the AP : 32, 27, 22, . . . is – 78?

OPtion

1) 35
2) 32
3) 29
4) 27
5) 20
6) 23
7) 21
8) 30
9) 25
10) None of the above

Solution

Here, a = 32, d = 32 – 27 = – 5 and an = – 78,
As:- an = a + ( n – 1) d,
– 78 = 32 + (n – 1)(– 5),
– 78 = 37 – 5n,
– 115 = – 5n,
So, n = 23

Correct Option: 6 Best Solution (1)

13 Nov 2020 PROBABILITY

If P(E) = 0.52, what is the probability of ‘not E’?

OPtion

1) 0.58
2) 1
3) -0.58
4) -1
5) 0.48
6) -0.48
7) 0.42
8) 2
9) 1.48
10) None of the above

Solution

We know that,
P(E)+P(not E) = 1
It is given that, P(E) = 0.52
So, P(not E) = 1-P(E)
Or, P(not E) = 1-0.52
∴ P(not E) = 0.48

Correct Option: 5 Best Solution (4)

12 Nov 2020 PERCENTAGE

An alloy contains 51 % of bronze. What quantity of alloy is required to get 370 g of bronze?

OPtion

1) 725.490
2) 944.2
3) 950
4) 1000
5) 980.5
6) 750.21
7) 830
8) 840.63
9) 952.32
10) None of the above

Solution

Let the quantity of alloy required = x g
Then 51 % of x =370 g
51/100 × x = 370 g
x = (370 × 100)/51 g
x = 37000/51 g
x = 725.490 g

Correct Option: 1 Best Solution (3)

11 Nov 2020 AVERAGE

The average age of a family of 18 members is 82 years. If the age of the youngest member is 12 years, the average age of the family at the birth of the youngest member was?

OPtion

1) 75
2) 70
3) 78
4) 95
5) 85
6) 72
7) 82
8) 92
9) 79
10) None of the above

Solution

Total age of the family of 18 members = 82* 18 = 1476 yrs
Total age of the family members 12 yrs ago = 1476 - (18*12) = 1260
At the time total members in a family = 18
Average age of the family at the birth of the youngest member = 1260/18 = 70yrs.

Correct Option: 2 Best Solution (3)

10 Nov 2020 sequence

0,1,-1,8,4,29,23...............
next number of the sequence will be

OPtion

1) 29
2) 34
3) 38
4) 44
5) 50
6) 63
7) 72
8) 69
9) 84
10) none of these

Solution

0+1^2 = 1
1-2 = -1
-1+3^2 = 8
8-4 = 4
4+5^2 = 29
29-6 = 23
23+7^2 = 72

Correct Option: 7 Best Solution (1)