At a meeting, 25 attendants used a pencil and 15 attendants used a pen. If exactly 20 attendants used only one of the two types of writing tools, how many attendants wrote with both types of writing tools?
Choose the correct option:	A) 10	B) 6	C) 7	D) 4	E) 14
Say x attendants wrote with both writing tools.   (25 - x) + (15 - x) = 20 --&gt; x = 10.   10nswer: 10.
<result>A</result>
At a meeting, 25 attendants used a pencil and 15 attendants used a pen. If exactly 20 attendants used only one of the two types of writing tools, how many attendants wrote with both types of writing tools?