Question

A 100 gram block is placed on a scale that is known to have a 12% error. What will the scale read?

Answer 1

The scale will read 112 grams.

Why?

Since we already know the percent error of the scale (12%) and we also know the mass of the block that is placed on the scale, we can calculate what will be the read of the scale by using the following formula:

$ScaleRead=100g+(100g*\frac{12}{100})=100g+(100g*0.12)=100g+12g\\\\ScaleRead=112g$

We can see that the scale will read 112 grams.

Let's verify that we are right by using the following formula to verify if the obtained value for the scale read will be 12%:

$PercentError=\frac{ActualValue-RealValue}{RealValue}*100=\frac{112g-100g}{100g}*100\\\\PercentError=\frac{12g}{100g}*100=0.12*100=12(percent)$

Hence, we can see that the scale will read 112 grams.

Have a nice day!