Answer: that will be basically 1 hour and 10 mins
Explanation:
Machine A provide 1 yo-yo for 5mins, there for in 10mins. Of machine A = 2 yo-yo
While machine B provides 1 yo-yo in 10mins.
Which gives us total of
3 every 10 mins
Therefore,
20/3 = 6 remainder 2
Which finally gives us
(6 2/3) x 10