The first step is to find out how question in total she is able to miss, while still passing.
We know that there are [tex]40\\[/tex] questions on the test and she must get [tex]70[/tex]% of the questions correct.
Let's calculate how many questions that is:
40 x 0.70
= 28.
Subtract
40 - 28
= 12.
She is able to get 12 answers incorrect.
Now we must find out how many questions she got wrong when she got 40% of the first 15 correct.
If she got 40% correct; She got 60% incorrect.
Let's do the math:
Multiply:
15 x 0.40
= 6
Subtract:
15 - 6
= 9
This means that she got 6 questions correct, and 9 questions incorrect.
With the total allotment of 12 incorrect answers allowed, she can only get 3 more questions wrong.
Now we must find the percentage of the remaining 25 questions she can get wrong.
She can only get 3 wrong and she must get 22 correct.
Multiply:
22 x 4
= 88.
This means that she has to get 88% of the remaining 25 questions correct.
