|
Bravo!
Answer
:
16
correct, 10 incorrect
Let's denote the number of correct answers as ( C )
and the number of
incorrect answers as ( I ). The father pays $5.00 for
each correct
answer and receives $8.00 for each incorrect answer.
The total amount the father pays is \( 5C \), and the total amount the
son pays is ( 8I ).
According to the problem, no money was exchanged, so: [ 5C - 8I =
0 ]
Now, we know that the boy answered a total of 26 questions:
[ C + I = 26 ]
Now, we have a system of two equations:
[ begin{cases} 5C - 8I = 0
C + I = 26 end{cases} ]
We can solve this system to find the values of ( C )
and I ).
One way to solve it is to multiply the second equation by 8 and add it
to the first equation to eliminate ( I ):
[ \begin{cases} 5C - 8I = 0 \\ 8(C + I) = 8 times
26 end{cases} ]
This simplifies to:
[ begin{cases} 5C - 8I = 0 8C + 8I =
208 end{cases} ]
Now, add the two equations:
[ 5C - 8I + 8C + 8I = 0 + 208 ]
Combine like terms:[ 13C = 208 ]
Divide by 13:
[ C = 16 ]
Now that we know ( C ), substitute it back into the
second equation to find ( I ):
[ 16 + I = 26 ]
Subtract 16 from both sides:
[ I = 10 ]
So, the boy got 16
correct answers and 10 incorrect answers. |
|
|
|
|
|
|
Brain
Teaser Of The
Day
How
Brain Teasers Help You
Stimulate
your brain cells.
Improve
your concentration.
Increase your fluid intelligence.
Reduce
brain deterioration.
Fill in the form below.
Receive one brain teaser a day.
Enter your email
here.
We take your
privacy very seriously.
Your information is never sold or shared.
|
|
|
|
|
|
|