- #1
johnhuntsman
- 76
- 0
The manager of a fast food restaurant determines that the average time that her customers wait for their food is 2.5 minutes. The manager wants to advertise that anybody who isn't served within a certain number of minutes gets a free hamburger. She doesn't want to give away free hamburgers to more than 2% of her customers. What should the advertisement say?
I'm solving for [itex]t[/itex]:
[itex]\int_ 0.4e^{-t/2.5}~dt=0.02[/itex]
[itex]-e^{-t/2.5}=0.02[/itex]
[itex]0=0.02+e^{-t/2.5}[/itex]
Take the natural logs and add [itex]-t/2.5[/itex] to get it back on the other side.
[itex]t/2.5=-3.91[/itex]
[itex]t=-1.56[/itex]
The answer is ten minutes. What did I do wrong?
I'm solving for [itex]t[/itex]:
[itex]\int_ 0.4e^{-t/2.5}~dt=0.02[/itex]
[itex]-e^{-t/2.5}=0.02[/itex]
[itex]0=0.02+e^{-t/2.5}[/itex]
Take the natural logs and add [itex]-t/2.5[/itex] to get it back on the other side.
[itex]t/2.5=-3.91[/itex]
[itex]t=-1.56[/itex]
The answer is ten minutes. What did I do wrong?
Last edited: