SOLUTION: If Machine A makes a yo-yo every five minutes and Machine B takes ten minutes to make a yo-yo, how many hours would it take them working together to make 20yo−yos?

Question 1197199: If Machine A makes a yo-yo every five minutes and Machine B takes ten minutes to make a yo-yo, how many hours would it take them working together to make 20yo−yos?
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.
If Machine A makes a yo-yo every five minutes and Machine B takes ten minutes to make a yo-yo,
how many hours would it take them working together to make 20 yo−yos?
~~~~~~~~~~~~~~~~

We assume that both machines started simultaneously.


Every 10 minutes, machine A produces 2 yo-yo; every 10 minutes machine B produces 1 yo-yo.

So, two machines produce 3 yo-yo every 10 minutes.


Divide 20 by 3 with a remainder: 20/3 = 6 + 2/3.

It tells you that in 6*10 = 60 minutes two machines will produce 6*3 = 18 yo-yos,
which is still less than 20 yo-yous.


In the next 5 minutes, machine A will produce the 19-th yo-yo.
In the next 5 minutes, machine A will produce the 20-th yo-yo, and machine B will complete the 21-th yo-yo.


Thus 20 yo-yo (and even 21 (!) yo-yo) will be completed 70 minutes after start moment.


70 minutes is the minimal time to wait to have 20 yo-yos completed.

Solved, with full explanations.

RELATED QUESTIONS
If Machine A can make a yo-yo every 5 minutes and Machine B can make a yo-yo every 10... (answered by josgarithmetic,math_tutor2020,ikleyn)

If machine A makes a yo-yo (answered by richwmiller)

If Machine A makes a... (answered by richwmiller)

The length of a string from the center of a yo-yo to its point of contact with Tony's... (answered by greenestamps)

A yo-yo factory has fixed operating costs of $575,000 per year. In addition to the fixed... (answered by addingup)

how do yo solve a word problem (answered by Alan3354)

Lydia holds the end of a yo-yo string 0.9 metres from the ground and swings the yo-yo in... (answered by ikleyn)

If a pencil costs .50, a ball costs $1.00 and a yo yo costs $1.50 and you have $5.00 how... (answered by checkley77)

how yo draw √14 on a number... (answered by checkley77,aksinghsecurity1@gmail.com)