Ex 15.1, 5
An organization selected 2400 families at random and surveyed them to determine a relationship between income level and the number of vehicles in a family. The information gathered is listed in the table below:
Suppose a family is chosen, find the probability that family chosen is
(i) earning Rs 10000 − 13000 per month and owning exactly 2 vehicles.
Number of total families surveyed = 2400
Number of families earning Rs 10000 − 13000 per month and owning exactly 2 vehicles = 29
Hence, required probability, P = 29/2400
Ex 15.1, 5
(ii) earning Rs 16000 or more per month and owning exactly 1 vehicle
Number of total families surveyed = 2400
Number of families earning Rs 16000 or more per month and owning exactly 1 vehicle = 579
Hence, required probability, P = 579/2400
Ex 15.1, 5
(iii) earning less than Rs 7000 per month & does not own any vehicle
Number of total families surveyed = 2400
Number of families earning less than Rs 7000 per month & does not own any vehicle = 10
Hence, required probability = P = 10/2400 = 1/240
Ex 15.1, 5
(iv) earning Rs 13000 – Rs16000 per month & owning more than 2 vehicles
Number of total families surveyed = 2400
Number of families earning Rs 13000 – Rs16000 per month & owning more than 2 vehicles = 25
Hence, required probability = P = 25/2400 = 1/96
Ex 15.1, 5
(v) owning not more than 1 vehicle
Number of total families surveyed = 2400
Number of families owning not more than 1 vehicle
= Number of families owning 0 vehicles
+ Number of families owning 1 vehicle
= (10 + 0 + 1 + 2 + 1) + (160 + 305 + 535 + 469 + 579)
= 2062
Hence, required probability = P = 2062/2400 = 1031/1200

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.