Question

Each polio consists of 4 doses and rack measles vaccination consists of 2 doses.Last year potter gave out a total of 60 vaccinations and that consisted of a total 128 doses.How many polio vaccinations and how many measles vaccinations did dr potter give last year?

Answer 1

4 polio

56 measles

Explanation:

Write equations to represent the problem

let x be the number of vaccinations for polio

let y be the number of vaccinations for measles

x + y = 60 Equation for vaccinations

4x + 2y = 128 Equation for doses

Solve the system using substitution. Rearrange x + y = 60 to isolate one variable.

x = 60 - y

Substitute x for 60-y in the other equation

4x + 2y = 128

4(60-y) + 2y = 128 Distribute over brackets

240 - 4y + 2y = 128 Collect like terms. They have the variable "y"

240 - 2y = 128 Subtract 240 from both sides

-2y = 128 - 240

-2y = -112 Divide both sides by -2

y = -112/-2

y = 56 Number of measles vaccinations

Substitute y for 56 in x + y = 60

x + y = 60

x + 56 = 60

x = 60 - 56

x = 4 Number of polio vaccinations

Therefore Dr. Potter gave out 4 polio vaccinations and 56 measles vaccinations.