Question 1192319
<br>
Since 20% use both, the 50% the use cell phone consist of 30% who use ONLY cell phone and 20% who use both.<br>
Likewise, the 40% who use paper consist of 20% who use ONLY paper and 20% who use both.<br>
So we have
30% who use cell phone only;
20% who use paper only; and
20% who use both.<br>
That's a total of 70% who use either cell phone or paper; that leaves 30% who use neither.<br>
ANSWER: 30%<br>