On a certain day, Tim invested $1,000 at 10 percent annual interest, compounded annually, and Lana invested $2,000 at 5 percent annual interest, compounded annually. The total amount of interest earned by Tim's investment in the first 2 years was how much greater than the total amount of interest earned by Lana's investment in the first 2 years?
(A) $5
(B) $15
(C) $50
Ans:A
我公式沒背錯呀,這題不是 T的複利-L的複利嗎?
怎都算不出答案勒?
