1.What's the combined area, in square inches, of the front and back of a rectangular sheet of paper measuring 8.5 inches by 11 inches?

a) 38 b)44 c)88 d)176 e)187

2. If money is invested at r percent interest, compunded annually, the amount of the investment will double in approximately 70/r years. If Pat's parents invested $5,000 in a long term bond that pays 8 percent interest, compunded annually. What will be the approximate total amount of the investment 18 years later, when Pat is ready for college?

a)$20,000 b)$15,000

第一题答案为E，只是我怎么也看不明白这道题在说什么。

第二题答案为A, 我用了很烦的方法才算出来，请问有没有什么简单的方法。

谢谢！

2题我是这么算得.18/(70/8)=72/25,total cost= 5000*2*72/35约为20,000

1题我也没明白.