Question

170

The following problems were in your worksheet on direct and inverse proportion. Reformulate the
relationships as algebraic expressions and remember to define the variables you use. You do not
have to solve the expressions.
5. The students in class usually drink a lot of water to help with their studies. I have found that
with five students in the class at least 30 litres of water is needed. How much water will be
needed when there are 30 students in the class?​

Answer 1

For s students, at least 6s liters of water will be needed. So, for 30 students, at least 6*30 = 180 liters of water will be needed.

Explanation:

This question is solved by proportions, using rule of three.

I am going to say that:

s is the number of students.

l is the number of liters of water needed for s students.

I have found that with five students in the class at least 30 litres of water is needed.

This means that:

`(s)/(l) = (5)/(30)`

`5l = 30s`

`l = (30s)/(5)`

`l = 6s`

This means that for s students, at least 6s liters of water will be needed. So, for 30 students, at least 6*30 = 180 liters of water will be needed.