Math-3rd root of W?

chaihuo

i came across this problem:

what is value of W third root?
1), W fifth root is 64
2), W fifteen root is 4

thought the answer whould be D, but noticed someone said it is B. Can you help to sovle this?

Thx

guqing28

From (1), we can reason that W~1/5 = 64 = 2 ~6, then W = 2 ~30, so W~1/3 = 2~10

From (2), that W~1/15 = 2~2  then W = 2 ~30  so w~1/3 = 2~10


the correct choice id ( D)

[此贴子已经被作者于2002-11-29 8:34:05编辑过]

chaihuo

Thanks, there.

rjch

Just a reminder, you do not need to calculate the result in real test.  When you know that you can get it from either condition, choose D and move on.  Time is precious.