Question

Three airports have a total of `225.2` million annual arrivals and departures. The second airport airport has `13.8` million more than the third airport. The first has `1.4` million more than the third airport. How many did each airport have?

Answer 1

see a solution process below;

Explanation:

We can say, let the three airports be `x, y, and z`

Where;

`x = "first airport"`

`y = "second airport"`

`z = "third airport"`

From the first statement;

`x + y + z = 225.2 - - - eqn1`

`y = z + 13.8 - - - eqn2`

`x = z + 1.4 - - - eqn3`

Substitute `eqn2 and eqn3` into `eqn1`

`z + 1.4 + z + 13.8 + z = 225.2`

`3z = 210`

Divide both sides by `3`

`(3z)/3 = 210/3`

`z = 210/3`

`z = 70 " million"`

Substituting the value of `z` into `eqn2`

`y = z + 13.8`

`y = 70 + 13.8`

`y = 83.8 " million"`

Substituting the value of `z` into `eqn3`

`x = z + 1.4`

`x = 70 + 1.4`

`x = 71.4 " million"`

Therefore;

`x = "first airport" = 71.4 " million"`

`y = "second airport" = 83.8 " million"`

`z = "third airport" = 70 " million"`

Answer 2

First airport has `71.4` million people

Second airport has `83.8` million people

First airport has `71.4` million people

Explanation:

We can use one variable to answer this question because we know the relationship between the number of passengers for the three airports.

Both the first and the second are given in terms of the third airport.

Let the number of passengers at the third airport be `x` million

`3 rd` has `x` million
`2nd` has `13.8` million more: `rarr" "x+13.8` million
`1st` has `1.4` million more: `rarr" "x +1.4` million

The total number of people is `225.2` million.

`x +x+13.8+x+1.4 = 225.2`

`3x +15.2 = 225.2`

`3x = 225.2 - 15.2`

`3x = 210`

`x = 70`

Third airport has `70` million people
Second airport has `70+13.8 = 83.8` million people
First airport has `70+1.4 = 71.4` million people

Check

`70+83.8+71.4 = 225.2`