Tuesday, May 23, 2017

CBSE Class 7 Maths - Data Handling - NCERT EXERCISE 3.4 (#cbsenotes)

Data Handling

EXERCISE 3.4
CBSE Class 7 Maths
CBSE Class 7 Maths - Data Handling - NCERT EXERCISE 3.4 (#cbsenotes)


Q1: Tell whether the following is certain to happen, impossible can happen but not certain.
(i) You are older today than yesterday.
(ii) A tossed coin will land heads up.
(iii) A die when tossed shall land up with 8 on top.
(iv) The next traffic light seen will be green.
(v) Tomorrow will be a cloudy day.

Answer:
(i) It is certain to happen.
(ii) It can happen but not certain.
(iii)It is impossible.
(iv) It can happen but not certain.
(v)  It can happen but not certain.




Q2: There are 6 marbles in a box with numbers from 1 to 6 marked on each of them.
(i) What is the probability of drawing a marble with number 2?
(ii) What is the probability of drawing a marble with number 5?


Answer:
Total marbles from 1 to 6 marked in a box = 6
(i) The probability of drawing a marble with number 2.
P (drawing one marble) = ⅙

(ii) The probability of drawing a marble with number 5.
P (drawing one marble) = ⅙



Q3: A coin is flipped to decide which team starts the game. What is the probability that your team will start?

Answer:

A coin has two possible outcomes Head and Tail.
Probability of getting Head or Tail is equal.
P (Starting game) =  ½

Other Questions:

Q4: A 5₹ coin is tossed, what are the possible outcomes?

Answer: Two outcomes i.e. either Head or Tail.


Q5: A box of 600 electric bulbs contains 12 defective bulbs. One bulb is taken out at random from this box. What is the probability that it is a non defective bulb?


Answer: Total electric bulbs = 600
        Defective bulbs = 12
        Non Defective bulbs = 600 - 12 = 588

        P (picking up non-defective bulb) = Non Defective bulbs ÷ Total bulbs = 588 ÷ 600 = 0.98






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