Question

A scale has a percent error of 5% the actual mass of a rock is 258g

This scale is likely to show the mass of either

245.1 253.0 256.7 257.5 g Or 259.3 259.5 263.0 270.9 g.

Please, pick them wisely, you can pick ONE for each side. And remember it's not percent its percent ERROR

Answer 1

245.1 and 270.9 since that actual weight of the rock is either 0.95 or 1.05 times the mass the scale shows.

If you want more explanation I'm more than happy to and I hope this helps:)

Answer 2

245.1 g or 270.9 g

Explanation:

Error in mass for the measurement is 5% of the actual mass . This simply means 5% of 258 grams. Mathematically,

error in mass = percentage error × actual mass

error in mass = 5 /100 × 258

error in mass = 1290/100

error in mass = 12.90 grams

Since the error in mass is 12.90 grams that means the scaled mass either has an increase of 12.9 g or decrease of 12.9 g from the actual mass.

scaled mass can be either 258 - 12.90 = 245.1 grams

or

258 + 12.90 = 270.9 grams