Question

How can I use the 5-D Process to solve this?

Answer 1

Part A. Define the variables and the equation.

Let y be the money Ling wants to save and x be the weeks, then we can write

`y=4x+23`

Part B. Solve the equation.

Since Ling wants $87, then y=87. By substituting this value into the last equation, we get

`87=4x+23`

then, by moving 23 to the left hand side, we have

`\begin{gathered} 87-23=4x \\ 64=4x \end{gathered}`

or equivalently,

`4x=64`

Finally, by moving 4 to the right hand side, we obtain

`\begin{gathered} x=(64)/(4) \\ x=16 \end{gathered}`

Then, How long will it take her to get enough money to buy the tickets? 16 weeks