Question

Evan has an exam worth fifteen percent of his grade. He has an overall grade of 84.7 percent. The exam has 40 questions. How many questions does he need to get right in order to pass with an overall grade of 70?

Answer 1

He needs to get 1 right

Explanation:

1/40 is equal to .025. This means the other 39/40 incorrect ones are worth .975(97.5%). If we multiply the .975 by the 15 percent of his overall grade, we get 14.625. When you subtract this from the overall grade, you get 70.075, which is just above a 70%.

Answer 2

For this case we have that the general qualification is 70, of it Evan has accumulated 84.7%. Making a rule of three:

70 ----------> 100%

x -------------> 84.7%

Where "x" represents the rating that Evan has accumulated:

`x = \frac {84.7 * 70} {100}\\x = 59.29\\70-59.29 = 10.71`

Evan is missing 10.71 to get 70.

In percentage, we have to:

100% -84.7% = 15.3%

Now we have that the exam represents 15% of the grade, this is divided into 40 questions.

It is observed that Evan must correctly answer the 40 questions of the exam, so he would get 15%. Even so, it would lack a 0.3% note to reach 70.

Answer:

He must answer the 40 questions correctly.