absolute value

Question

Ariel weighed an object on her balance and recorded a mass of 24.3
grams. Her teacher told her that there was obviously something wrong
with her balance because it was giving her a reading which was 30.0% too
high. What was the actual mass of the object?

Answer 1

Hi!  If her answer was 30% too high, that means it was 130% of what it was supposed to be.  130% of something means 1.3 times it (you know, just like 100% of something is 1 times it).

 

So 1.3 times the true mass is 24.3 grams.  We can write an equation:

 

1.3m = 24.3

 

And then just solve for m by dividing both sides of the equation by 1.3:)