Question 812206
In a group of 60 workers the average salary is $80 a day per worker.
 If some of the workers earn $75 a day and all the rest earn $100 a day,
 how many workers earn $75 a day?
:
Let x = no. of $75 per days workers
Since there are a total of 60 workers, we know that:
(60-x) = no. of $100 per day workers
:
{{{((75x + 100(60-x)))/60}}} = 80
multiply both sides by 60
75x + 6000 - 100x = 4800
75x - 100x = 4800 - 6000
-25x = -1200
x = -1200/-25
x = 48 workers earn $75 a day