a contestant makes $700 for every correct answer but loses $500 for every wrong answer. After answering 24 questions, Sarah broke even. How many questions did she answer correctly?
You can answer using any method you like, but the final result must be in ratio/proportion form. Please explain your reasoning.
2007-04-24 02:15:27 · 4 answers · asked by Arthur Q 3 in Science & Mathematics ➔ Mathematics
R = # of answers right
W = # of answers wrong
There were 24 questions, so:
R + W = 24
She broke even on money, so:
700 R = 500 W
Solve R + W = 24 for one variable.
W = 24 - R
Plug that into the other equation...
700 R = 500 (24 - R)
700 R = 12000 - 500 R
1200 R = 12000
R = 10
10 Right answers (and 14 Wrong answers)
2007-04-24 02:26:26 · answer #1 · answered by Mathematica 7 · 0⤊ 3⤋
As the contestant gets $700 for each correct answer and loses$500 for each wrong one and as finally she breaks even the ratio of wrong answer to right answer is
700:500
=7:5 Sum of the ratios=7+5=12
Therefore wrong answers=24*7/12=14.and
Right answers=24*5/12=10
2007-04-24 09:53:09 · answer #2 · answered by alpha 7 · 0⤊ 0⤋
She answered 10 answers correctly. How to solve this???
Let she answer 'x' questions correctly and 'y' questions wrongly.
And x + y = 24 (Since 24 questions were asked)
Since she breaks even then,
The money WON = The money LOST
Then 700x = 500y
Putting y = 24 - x in the above equation,
=> 700x = 500(24-x)
=> 700x = 12000 - 500x
=> 1200x = 12000
=> x = 10
So, she answered 10 correctly and 14 in-correctly
2007-04-24 09:22:43 · answer #3 · answered by Senthil 3 · 1⤊ 0⤋
she gets 5 rite for every 7 wrong so 10 rite and 14 wrong
i did dumb math i found out where 5 X 7 = 35 and figured it took 5 7's to get there and 7 5's to get there ad 5 + 7 = 12 questions
so you need to do it 2 times to get to the 24
2007-04-24 09:26:21 · answer #4 · answered by mobile auto repair (mr fix it) 7 · 1⤊ 0⤋