Pentex and Marbro, small companies in the stationery business, each had a dollar gross margin of $20,000 during September 2014. Pentex's September sales were twice that of Marbro's. If Pentex's gross margin as a percentage of sales for September was 10%, what was Marbro's gross margin as a percentage of sales for the same period?

20%

Explanation:

Since the gross margin is $20,000 and the gross margin percentage of Pentex is 10%, so from this information we can find out the sales value which is shown below:

Gross profit percentage = Gross profit : sales

10% = $20,000 : sales

So, the sales would be $200,000

Since the Pentex sales is twice of Marbro

So, the Marbro sales would be half of Pentex sales

So, the Marbro sales would be $100,000

Now the Marbro gross profit percentage would be

= $20,000 : $100,000

= $20%