Guess Teacher's Mass: 6.43, 60, 64.3, 600, 643 kg

[cupid.callin]

Homework Statement

A teacher measures and records her own mass to an accuracy of better than 1/2 percent. Which of the following is most likely the mass that she recorded?
(A)6.43 kg
(B)60 kg
(C)64.3 kg
(D)600 kg
(E)643 kg

The Attempt at a Solution

i know that answer is either B or C ( quite obvious :D )
but i can't understand how to use the term "to an accuracy of better than 1/2 percent"

.5% of 60 is .3

but what now?

 

[gneill]

Numbers have implied accuracy. 64.3 implies measurement accuracy of +/- 0.1 kg unless otherwise stated. 60 kg implies 60 +/- 1 kg. Which one conforms to the stated "within 1/2 a percent" accuracy?

 

[cupid.callin]

64.3 kg?

but how do you come up with error in each given mass?

 

[gneill]

64.3 kg?

but how do you come up with error in each given mass?

Have a look here:

http://www.chem1.com/acad/webtext/pre/mm3.html

Skim down to "Implied Uncertainty".