Question

A plane's average speed when flying from one city to another is 550 mi/h and is 430 mi/h on the return flight. To the nearest mile per hour, what is the plane's average speed for the entire trip?

Answer 1

`{\large{\boxed{\mathfrak{Question}}`

A plane's average speed when flying from one city to another is 550 mi/h and is 430 mi/h on the return flight. To the nearest mile per hour, what is the plane's average speed for the entire trip?

`{\large{\boxed{\mathfrak{Formula}}}`

The formula to find the average speed is distance divided by time

`{\large{\boxed{\mathfrak{Equation\:to\:find\:average\:speed}}}`

Let a be the average speed

`(1)/(550)+(1)/(430) =(2)/(a)`

Since we don't want our denominator's we will get rid of them by multiplying the
`LCM` between the two numbers.

Definition of LCM - The smallest quantity that is divisible by two or more given quantities, also known as Least Common Multiple

Multiply both sides by
`23650a` since that is our LCM.

Now our equation is

`43a+55a=47300`

`{\underline{simplify}}`

`98a=47300`

Since we want to isolate the average speed on one side or also known as
`a` we will divide both sides by 98

`a=482.653` miles per hour

`{\large{\boxed{\mathfrak{Answer}}}`

Our average speed is
`482.653` miles per hour or
`483` miles per hour

Answer 2

490 mi/h

Explanation: