Question

A card is drawn at random from a well-shuffled pack of cards numbered 1 to 20. Find the probability of (i) getting a number less than 7 (ii) getting a number divisible by 3

Answer 1

( {7}^{ - 1} - {8}^{ - 1} )^{ - 1}

Answer 2

Given,

Cards are numbered from 1 to 20.

To find,

The probability of (i) getting a number less than 7 (ii) getting a number divisible by 3.

Solution,

The probability of (i) getting a number less than 7 will be 3/10 and (ii) getting a number divisible by 3 will be 3/10.

We can easily solve this problem by following the given steps.

According to the question,

Cards are numbered from 1 to 20.

We know that the formula to find the probability of an event is given as follows:

Probability = Number of favourable outcomes/total number of outcomes

(i) Numbers less than 7 = 1,2,3,4,5,6

Total number of outcomes = 20

Probability of getting a number less than 7 = 6/20

Probability of getting a number less than 7 = 3/10

(ii) Numbers divisible by 3 = 3,6,9,12,15,18

Probability of getting a number divisible by 3 = 6/20

Probability of getting a number divisible by 3 = 3/10

Hence, the probability of (i) getting a number less than 7 is 3/10 and (ii) getting a number divisible by 3 is 3/10.