Answer:
It will take Machine A 20 additional minutes.
Step-by-step explanation:
First we have get the rate of work per hour, Machine A builds 1/2 of a car per hour, while Machine B builds 1/3 of a car per hour.
Using this we can determine the amount of work that has been done so far in one hour before Machine B broke down:
1/2 + 1/3 = 3/6 + 2/6 = 5/6
Now we can produce an equation accordingly to determine how much time it'll take machine a to finish the job:
5/6 + 1/2x = 1
1/2x = 1/6
x = 1/3 hours = 20 minutes
Note: In the question you typed "how much additional time will it take machine b to finish" but I think you meant machine a because machine b broke down. Please correct me if I'm wrong.
Hope this helps! And let me know if you have any questions!