Avril and Ben are surveying passing traffic, noting the number of occupants in each vehicle. Below is the table of results of their survey?

Avril and Ben are surveying passing traffic, noting the number of occupants in each vehicle. Below is the table of results of their survey.

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(i) How many vehicles passed Avril and Ben?

Based on these results, what is the probability that the next vehicle passing by:

(ii) has 2 occupants?

(iii) has 4 occupants?

(iv) has less than 4 occupants?

(v) has at least 3 occupants?

vi) If 6 000 vehicles pass the same spot, how many would one expect to contain more than 3 occupants? Answer to the nearest 10 vehicles.

vii) Avril did some calculations and expects that on Tuesday there will be 3520 vehicles without passengers pass the same spot. (ie. vehicles with only the driver in them). How many vehicles in total does Avril expect to pass on Tuesday?

1 Answer

This is all about expectation - the chart has given us a sample and now we can use it to predict outcomes. See below for details:

Explanation:

This is all about expectation - the chart has given us a sample and now we can use it to predict outcomes.

i - We need to know the total number of cars that are in the sample so that we can use that for the ratios and fractions in the following questions:

44+37+22+10+6+1+4=12444+37+22+10+6+1+4=124

ii: has 2 occupants: 37/12437124

iii: has four occupants: 10/124=5/6210124=562

iv: has less than 4 - and so it's 1, 2, and 3 occupants: 105/124105124

v: has at least 3 occupants - and so it's 3, 4, 5, 6, and more: 43/12443124

vi: if 6,000 cars pass by, how many would be expected to have more than 3 occupants?

With our sample, we have 21/12421124 that have more than 3 occupants. So we'd expect (using a ratio of our sample 21/12421124 and comparing it to a ratio of what we'd expect to the total number of cars expected):

21/124=x/600021124=x6000

124x=21xx6000124x=21×6000

x=(21xx6000)/124~=1016~=1020x=21×600012410161020 rounded to the nearest 10

vii: if 3520 single passenger vehicles are anticipated on a single day, the total number of cars anticipated is (using a ratio of single passenger cars in our sample and comparing it to a ratio of anticipated single passenger cars to the total number of cars):

44/124=3520/x44124=3520x

44x=124xx352044x=124×3520

x=(124xx3520)/44=9920x=124×352044=9920