A worm is at the bottom of a forty foot hole. It can crawl upwards at the rate of four feet in one day, but at night, it slips back three feet. At this rate, how long will it take the worm to crawl out of the hole?  Choose the correct choice from the following answers:  A) 33  B) 87  C) 37  D) 28  E) 921
Explanation:   For each day worm climb only 4 - 3= 
<gadget id="calculator">4 - 3</gadget>
<output>1</output>
1feet.   After 36 days worm reach the 36 foot.   Exactly the 37th day worm reach 40 foot and won't slips back.   Answer: 37
<result>C</result>
A worm is at the bottom of a forty foot hole. It can crawl upwards at the rate of four feet in one day, but at night, it slips back three feet. At this rate, how long will it take the worm to crawl out of the hole?