Maths
posted by Jannie on .
Multiplechoice questions in a test are graded by adding 2 marks for each correct
response and subtracting 1 mark for each incorrect response (including no response).
Rory and Jenny answered all the multiplechoice questions, with Rory scoring 27 and
Jenny scoring 42. Rory answered 19 questions correctly.
a How many multiplechoice questions were there?
b How many more questions than Rory did Jenny answer correctly?

i don't care / know

a.Rory
(19 correct ans X 2) 38
Rory's score 27
equals (incorrect ans)11 pts deducted
therefore
19 correct + 11 incorrect = 30 questions
b.jenny
Let x= correct answers
y= incorrect answers
equations:
2xy=42 eq1(which is the score of jenny)
x+y=30 eq2(total no. of items)
use elimination method
then:
3x=72
divided both sides by 3
x=24
substituting to eq.1
2xy=42
2(24)y=42
48y=42
y=4842
y=6
or substituting to eq.2
x+y=30
24+y=30
y=3024
y=6
therefore
jenny got 24 correct answers and 6 incorrect answers. 
Answer for Jenny bought a gallon of orange juice. The recipe for punch calls for 2 quarts of juice. How many quarts will she have left over to drink at breakfast.

Screw you!!!