One machine took 90 minutes while another took 40 minutes
to produce the same number of similar can drinks.
The drink-making rate of the first machine is x drinks per
90 minutes or
or 
.
The drink-making rate of the second machine is x drinks per
40 minutes or
or 
.
The faster machine produced 40 more can drinks per minute
than the slower one.







Multiply both sides by LCD = 360
So the slower machine's drink-making rate is

=

=

And the faster machine's drink-making rate is

=

=

If both machines were switched on at the same time,
what was the total number of can drinks produced after 6 hours
6 hours is 6*60 or 360 minutes.
In 360 minutes the slower machine will produce 32*360 or 11520 drinks.
In 360 minutes the faster machine will produce 72*360 or 25920 drinks.
11520 drinks + 25920 drinks = 37440 drinks.
Edwin