Which of the following random variables is not discrete?

a) the number of classes taken in one semester by a student

b) the annual rainfall in a city

c) the attendance at a football game

d) the number of patients treated at an emergency room in a day

b) The annual rainfall in a city

Step-by-step explanation:

Remember, a discrete variable is one that can only take a finite number of values between any two values of a characteristic and a continuous variable is one that can take an infinite number of values between any two values of a characteristic.

a) Observe that the variable x='classes taken in one semester' can take the values 0,1,2,...,n.

Then the variable x is discrete

b) Observe that the variable x='annual rainfall in a city' can take the values 2in, 1.6in, 5.1 in, 0.1in

Then, the variable x can be take a infinite number of values between two number. So x isn't a discrete variable.

c) The variable x='attendance at a football game' can take the values 3000,5000... n. And never will be a decimal number because There cannot be a personal decimal number. Therefore, x is a discrete variable.

d) The variable x='patients treated at an emergency room in a day' can take the values 1,2,3,...,n. And never will be a decimal number because There cannot be a personal decimal number. Therefore, x is a discrete variable.

50%

Step-by-step explanation:

I'm converting 7kg to grams to make it easier. So £10 = 7000g

£1 = 7000÷10 = 700g

700g÷2 = 350g and if you follow the ratios on top, she payed 50p per 350g

She sells a bag of 350g for 75p.

Percentage profit= × 100

75p - 50p = 25p = change in cost

Percentage profit= × 100

= 50%