Question

3. Dr. Potter provides vaccinations against polio and measles. Each polio vaccination consists of 5

doses, and each measles vaccination consists of 3 doses. Last year, Dr. Potter gave a total of 60
vaccinations that consisted of a total of 225 doses. How many more measles vaccines did Mr.
Potter give than polio?

Please explain the process. THX

Answer 1

There are 15 more measles vaccines than polio vaccines

Explanation:

Represent Polio with P and Measles with M

Given

5P + 3M = 225

P + M = 60

Required

How much is M greater than P; M - P

Make M the subject of formula in the second equation

`M = 60 - P`

Substitute this in the first equation

`5P + 3M = 225` becomes

`5P + 3(60 - P) = 225`

Open the bracket

`5P + 180 - 3P = 225`

Collect Like Terms

`5P - 3P = 225 - 180`

`2P = 45`

Divide both sides by 2

`P = 22.5`

Substitute 22.5 for P in
`M = 60 - P`

`M = 60 - 22.5`

`M = 37.5`

Calculate the difference; M - P

`M - P = 37.5 - 22.5`

`M - P = 15`

Hence, there are 15 more measles vaccines than polio vaccines