Machine A produces bolts at a uniform rate of 120 every 40 seconds and Machine B produce bolts at a uniform rate of 100 every 20 seconds. If the two machines run simultaneously, how many seconds will it take for them to produce a total of 200 bolts?

Question: Machine A produces bolts at a uniform rate of 120 every 40 seconds and Machine B produce bolts at a uniform rate of 100 every 20 seconds. If the two machines run simultaneously, how many seconds will it take for them to produce a total of 200 bolts?

Solution:
Given
Machine a produces bolts at a uniform rate of 120 every 40 second
∴ machine a produce 120/40 = 3 bolts per second

Machine b produces bolts at a uniform rate of 100 every 20 second
∴ machine b produces 100/20 = 5 bolts per second

Both machine produce 3 + 5 = 8 bolts running simultaneously per second.

Machine produces 8 bolts for 1 second
∴ For 200 bolts the time taken is 200/8 seconds
= 25 seconds

The machine takes 25 seconds to produce 200 bolts.