Alanna can detail a car in 45 minutes. robbie can detail a car in 30 minutes. if they work together, how many minutes does it take them to detail a car?

a.) 15 minutes
b.) 18 minutes
c.) 75 minutes
d.) 90 minutes

Amount of time needed by Alanna to detail a car = 45 minutes
Amount of time needed by Robbie to detail a car = 30 minutes
Then
The time needed by
Alanna and Robbie to detail a car together = (30 * 45)/(30 + 45) minutes
                                                                     = 1350/75 minutes
                                                                     = 18 minutes

From the above deduction, we can conclude that the correct option among all the options that are given in the question is the second option or option "B". I hope it helped you.

Any pictures or something i need more info