If 20 typists can type 50 letters in 30 minutes, then how many letters will 40 typists working at the same rate complete in 1 hour?	Choose one:	A) 400	B) 500	C) 350	D) 250	E) 200
No. of letters typing by 20 typists in 30 minutes = 50   No. of letters typing by 20 typists in 60 minutes = 50*2= 
<gadget id="calculator">50*2</gadget>
<output>100</output>
100   No. of letters typing by 40 typists in 60 minutes= 100/10*40= 
<gadget id="calculator">100/10*40</gadget>
<output>400</output>
400   400nswer : 400
<result>A</result>
If 20 typists can type 50 letters in 30 minutes, then how many letters will 40 typists working at the same rate complete in 1 hour?