Answer to Question #210351 in Statistics and Probability for Khomotso

Question

In a certain area, 50% of the household are using electricity as a source of energy, 30% are using parrafin and 20% are using coal. The users of electricity use 25% for cooking ,25% for lighting,20% for heating and 30% for small appliances. Coal is used for only cooking, and parraffin is used for cooking (50%) , heating (25%) and lighting (25%).

1. Summarise all the possible energy usage outcomes using a tree diagram and write the probability values on the branches.

2. What is the probability that a random choosen household will be using electricity for lighting?

Answer 1

Tree Diagram

                                                                    

                                                     

Electricity 50/100=1/2

Paraffin 30/100=3/10

Coal 20/100=1/5

Electricity (cooking) 25/100*1/2=1/8

Electricity (Lighting) 25/100*1/2=1/8

Electricity (heating) 20/100*1/2=1/10

Electricity (small) 30/100*1/2=3/20

Paraffin (cooking) 50/100*3/10=3/20

Paraffin (heating) 25/100*3/10=3/40

Paraffin (lighting) 25/100*3/10=3/40

Coal (cooking) 100/100*1/5= 1/5

Probability for using electricity for lighting=1/8