CBSE Class 12 Mathematics Probability Worksheet Set 04

CBSE Class 12 Mathematics Probability Worksheet Set A

More Questions

Examples of value based questions ( Answers are provided for value based questions only )

Q1) An insurance company insured 2000 scooter drivers, 4000 car drivers and 6000 truck drivers. The probability of an accident involving a scooter driver, car driver and a truck is 0.01, 0.03 and 0.15 respectively. One of the insured persons meets with an accident. What is the probability that he is a scooter driver? Write down any two practices that would enhance road safety.

Ans – 1) Obeying traffic signals

        2) Not using cell phones while driving

       3) Proper maintenance of vehicles. 4) Moving within the speed limit

Q2) In a test, an examinee either guesses or copies or knows the answer to a multiple choice question with four choices. The probability that he makes a guess is 1/3 and the probability that he copies the answer is 1/6. The probability that his answer is correct, given that he copied it, is 1/8. Find the probability that he knew the answer to the question, given that he correctly answered it. Copying is akin to using a painkiller. Explain the analogy.

Ans – Painkillers do not provide cure for the infection. They merely relieve us of the pain (a symptom). Similarly copying in exams will not help us sort out our trouble in the subject. It only postpones it for another day.

Q3) In a group consisting of equal number of men and women, 10% men and 45% women are unemployed. What is the probability that a person selected at random is employed? Suggest 2 steps to enhance employability of youth.

Ans - 1) Education up to class 12th (minimum)

        2) Acquiring soft skills

        3) Acquiring linguistic skills

       4) Cultivating working qualities like responsibility and team work

       5) enrolling in vocational courses

Q4) A group contains 10 men and 4 women. A three member committee is formed from the group, containing at least 1 woman. Find the probability that the committee so formed has more women than men. Write any 2 benefits of including more women in Panchayat committees.

Ans – 1) Family needs will be addressed faster 2) Gender bias and social evils targeted at women will wane 3) Needs of women will come to the fore and improve self confidence amongst them

Q5) Three rifle men take one shot each at the same target. The probabilities of the first, second and third rifle men hitting the target are 0.4, 0.5, 0.8 respectively. Find the probability that exactly 2 of them hit the target. The National Cadet Corps (NCC) provides opportunities for training in gun firing. Write 2 benefits of students joining NCC.

Ans – 1)Personal discipline 2) acquiring survival skills 3) team spirit and learning to work as a team 4) patriotism 5) Care for others and social service

Q6) A lot of 100 bulbs from a manufacturing unit is known to contain 10 defective and 90 non- defective bulbs. If a sample of 8 bulbs is selected at random, what is the probability that a) the sample has 3 defective and 5 non-defective bulbs. b) The sample has at least 1 defective bulb. Write two advantages of using CFL (Compact fluorescent lamp) bulbs over incandescent bulbs.

Ans – 1) Uses energy more efficiently (saves energy)

2) lower price

3) Brighter

4) Releases lesser amount of heat.

Q7) A shopkeeper has 5 customers who rent his cycles. He has 3 cycles and the probability that a customer will a hire a cycle for a day is 3/4. If he charges Rs. 2 as rent for a cycle, find the probability that he earns exactly Rs. 6 per day. Give 2 advantages of using bicycles.

Ans – 1) Eco- friendly (no pollution)

2) health benefits of individual

3) lower price

4) Relieves parking menace

5) Saves energy