$90 profit would be made on 6 dozen calculators.
SOLUTION:
Cost per calculator: 85/12
Revenue per calculator: 25/3
Profit per calculator:
Profit = revenue - cost
Profit = (25/3) - (85/12) = 1.25
Profit made on six dozen calculators:
6 x 12 x 1.25 = 90
If they were sold at $25 for 3 calculators, that means the 12 calculators were sold for $100.
6 dozen is 72, meaning there were 24 sets of calculators that were sold in 3s (24 x 25 = $600).
Since one dozen was purchased for $85, then 6 dozen were purchased for $510.
Hence, 6 dozen calculators were bought for $510 and sold for $600.
The profit is $90 ($600 - $510).
Tip: Cost, revenue and profit are the three most important factors in determining the success of your business. A business can have high revenue, but if the costs are higher, it will show no profit and is destined to go out of business when available capital runs out. Managing costs and revenue to maximize profit is key for any entrepreneur. Read more at Chron.com.