Value of 3rd root of -89

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Fri Aug 21, 2009 9:35 am

Value of 3rd root of -89

by alex10 » Sat Aug 29, 2009 6:46 am
Hi,

I am facing problems with the following question:

The value of the 3rd root of -89 is between...

A: -9 and -10
B: -8 and -9
C: -4 and -5
D: -3 and -4
E: undefined

How to approach such a question?

OA: ...C...

Thanks!
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Sat Aug 29, 2009 7:04 am
For option C, (-4)^(3)=-64 and (-5)^(3)=-125. Some number between -4 and -5 when cubed should give you -89.

Junior | Next Rank: 30 Posts
Posts: 24
Joined: Fri Aug 21, 2009 9:35 am

by alex10 » Sat Aug 29, 2009 7:10 am
Thanks a lot!