A test has 40 questions. If Marcel got 75% correct, how many questions did Marcel get wrong?

Question

this is a question i have been stuck on for days now i just dont know what to do 

Answer 1

Hi, Nadia.

 

For this problem, remember that a percentage is a part out of 100. If he got, 75% correct, he got the remaining 25% incorrect (because 75% + 25% = 100%). Also, 25% is expressed in fraction form as 25/100 and in decimal form as 0.25 (25 hundredths).

 

We now can solve one of two ways:

 

I) We can set up a proportion

   amount wrong (x)/total amount (40) = 25/100

   x/40 = 25/100... Multiple both sides by 40...

   x = 1000/100 = 10

 

II) We can multiple 40 by 25% in decimal form (0.25). 40 * 0.25 = 10

 

Either way you get 10.