(發問) 天山 04-11

[flyflyy]

At the end of each year, the value of a certain antique watch is c percent more than its value one year earlier, where c has the same value each year. If the value of the watch was k dollers on Jan.1, 1992, and m dollars on Jan. 1, 1994, then in terms of m and k, what was the value of the watch, in dollars, on Jan. 1, 1995?

A. m+1/2(m-k)
B. m+1/2[(m-k)/K]m
C. m√m/√k
D. m*m/2k
E. km*m

答案是C
可以請大大幫我解答一下嗎?
增值C percent的部份要怎麼代進去?
感恩~~

[sweetymanman]

1992: K
1993: K*(1+c%)
1994: K*(1+c%)[sup]2[/sup]=m -> (1+c%)[sup]2[/sup]= m/k->1+c%=√m/√k

1995: K*(1+c%)[sup]3[/sup]=m -> k*(1+c%)[sup]2[/sup]*(1+c%)=m*(1+c%)=m*√m/√k

ans:c