Give the step-by-step reasoning process and then the final answer. Jack went to a supermarket with $100 and bought 4 bottles of water. Then his mother called him and asked him to buy twice as many bottles as he already bought. Each bottle cost $2. Finally, he also bought half a pound of cheese and 1 pound of cheese costs $10. How much money does Jack have remaining?
Jack's mother asked him to buy 2 * 4 = 8 bottles of water. Thus Jack bought 4 + 8 = 12 bottles of water in total. Altogether, the bottles of water cost 12 * $2 = $24. The cheese cost 1 / 2 * $10 = $5. So Jack spent $24 + $5 = $29 on water and cheese. Since he started with $100, he now has $100 - $29 = $71 left.
The final answer: 71.