Searching for "5%"

Q:

A man buys a watch for Rs. 1950 in cash and sells it for Rs. 2200 at a credit of 1 year. If the rate of interest is 10% per annum, the man:

A) gains Rs. 55 B) gains Rs. 50
C) loses Rs. 30 D) gains Rs. 30
 
Answer & Explanation Answer: B) gains Rs. 50

Explanation:

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Q:

The probabilities that A and B will tell the truth are 2 / 3 and 4 / 5 respectively . What is the probability that they agree with each other ?

A) 3/5 B) 1/3
C) 2/5 D) 3/4
 
Answer & Explanation Answer: A) 3/5

Explanation:

Let A be the event of A will tell truth. B be the event of B tell truth

 

 P(A)=23,P(Ac)=1-P(A)=13

 

 

 

P(B)=45,P(Bc)=1-P(B)=15 

 

When both agree then they say true or they say false together, that is 

 

 AB or AcBc

 

 

 

Also these events will be mutually exclusive :

 

 P(AB)+P(AcBc)=P(A)P(B)P(C)=23*45+13*15=35

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Q:

The probabilities that drivers A, B and C will drive home safely after consuming liquor are 2 / 5, 3 / 7 and 3 / 4, respectively. What is the probability that they will drive home safely after consuming liquor ?

A) 3/70 B) 4/70
C) 9/70 D) 1/50
 
Answer & Explanation Answer: C) 9/70

Explanation:

Let A be the event of driver A drive safely after consuming liquor. 

 

Let B be the event of driver B drive safely after consuming liquor. 

 

Let C be the event of driver C drive safely after consuming liquor. 

 

P(A)=2/5,P(B)=3/7,P(C)=3/4

 

The events A, B and C are independent . Therefore,

 

PABC=P(A)P(B)P(C)=25*37*34=970

 

Therefore, The probability that all the drivers will drive home safely after consuming liquor is 9/70

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Q:

The odds favouring the event of a person hitting a target are 3 to 5. The odds against the event of another person hitting the target are 3 to 2. If each of them fire once at the target, find the probability that both of them hit the target.

A) 1/20 B) 4/20
C) 1/20 D) 3/20
 
Answer & Explanation Answer: D) 3/20

Explanation:

Let A be the event of first person hitting the target,

P(A) =33+5=38  (odd in favour)

Let B be the event of Second person hitting a target.

P(B)=23+2=25 (odd against)

Since both events are independent and both will hit the target so,

P(AB)= P(A)P(B)=38×25=320

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Q:

A three-digit number is formed with the digits 1, 2, 3, 4, 5 at random. What is probability that number formed is divisible by 5 ?

A) 1/4 B) 1/5
C) 1/2 D) 3/4
 
Answer & Explanation Answer: B) 1/5

Explanation:

If a number ends with 5, 0 then the number will be divisible by 5
Here only 5 is present, end place will be fixed by 5 so, 

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Q:

Course materials are sent to students by a distance teaching institution. The probability that they will send a wrong programme’s study material is 1/5. There is a probability of 3/4 that the package is damaged in transit, and there is a probability of 1/3 that there is a short shipment. What is the probability that the complete material for the course arrives without any damage in transit? 

A) 4/5 B) 2/3
C) 1/2 D) 2/15
 
Answer & Explanation Answer: D) 2/15

Explanation:

Probability of sending the correct material is 4/5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Probability of the material not being damaged in transit is 1/4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Probability that there is no short shipment = 2/3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

∴ Required probability =4/5 x 1/4 x 2/3 = 2/15

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Q:

A coin is tossed 5 times. What is the probability that head appears an odd number of times?

A) 1/2 B) 1/3
C) 2/3 D) 1
 
Answer & Explanation Answer: A) 1/2

Explanation:

The possible outcomes are as follows :

5H, 5T, (H, 4T), (T, 4H), (2H, 3T) (3H, 2T), i.e. 6 outcomes in all.

Therefore the probability that head appears an odd number of times = 3/6 =1/2 (In only three outcomes out of the six outcomes, head appears an odd number of times).

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Q:

A brother and a sister appear for an interview against two vacant posts in an office. The probability of the brother’s selection is 1/5 and that of the sister’s selection is 1/3. What is the probability that only one of them is selected?

A) 1/5 B) 3/4
C) 2/5 D) 3/5
 
Answer & Explanation Answer: C) 2/5

Explanation:

Probability that only one of them is selected = (prob. that brother is selected) × (prob. that sister is not selected) +  (Prob. that brother is not selected) × (Prob. that sister is selected)

 

15*23+45*1325

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Filed Under: Probability