Question

求这道英文数学题是什么意思并解决。急用！！！O(∩_∩)O谢谢！！！

Supppose a conservation campaign, together with higher rates caused demand for
electricity to increase at only 3% per year. Find the number of years before exactly
twice as much electricity is needed.

Answer 1

假定有一个环保运动，要求每年的电力仅以3%的速度增长，问，需要多少年电力能够翻一番？
答：设需要x年，那么有（1+0.03）^x=2,解得 x=23.45年，取整。

Answer 2

(1+0.03)^n=2
n=ln2/1n1.03=23年

Answer 3

假设一守恒运动，在一起较高的比率造成电力需求的增加仅以每年3%。找到恰好使电力需求是2倍的那一年的值。