144 ways because 12 songs 12 ways 12*12
If he answered 3 questions correctly, then the number of questions is got wrong is 7 and the number of questions that he did not attempt is 5.
<h3>What is the linear system?</h3>
A linear system is one in which the parameter in the equation has a degree of one. It might have one, two, or even more variables.
In a class test of 15 questions, (+4) marks are given for every correct answer, (– 2) marks are given for every incorrect answer, and 0 marks are given for questions that are not attempted. Punit scored (– 2) marks.
If he answered 3 questions correctly, then the number of the question are got wrong and the number of the question that he did not attempt.
Let x be the correct question and y be the incorrect question, z be the number of questions that he did not attempt, and A be the number of the total score. Then we have
4x – 2z = A
x + y + z = 15
If A = -2 and x = 3, then we have
4 × 3 – 2z = -2
12 + 2 = 2z
z = 7
Then the value of y will be
3 + y + 7 = 15
y = 5
More about the linear system link is given below.
brainly.com/question/20379472
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1 )
1st and 2nd equation (multiply 1st by -2 ):
-2x - 10 y + 8 z = 20
2 x - y + 5 z = -9
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- 11 y + 13 z = 11 / * ( -20 )
1st and 3rd:
- 2 x - 10 y + 8 z = 20
2 x - 10 y - 5 z = 0
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- 20 x + 3 z = 20 / * 11
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220 y - 260 z = -220
- 220 y + 33 z = 220
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z = 0, y = -1, x = - 5
2 )
2 x - y + 5 = -4
- 2 x + 3 y - 5 = - 10
Substitution: y = 2 x + 9
- 2 x + 3(2 x + 9 ) = -5
4 x = - 32, x = -8, y = -7, z = 5
3 )
x + y + z = 11
1.5 x+3 y +1.5 z = 21
x = 2 y
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3 y + z = 11 / * (-2)
6 y + 1.5 z = 21
------------------------
- 6 y - 2 z = -22
6 y + 1.5 z = 21
------------------------
-0.5 z = -1, z = 2, y = 3, z = 6
Answer: the store used 6 pounds of peanuts, 3 pounds of almonds and 2 pounds of raisins.
The measurements are in inches but the answer needs to be in feet, so we'll convert the numbers to feet first.
6"=1/2 ft
2"=1/6 ft
3"=1/4 ft
V=l×w×h
V=1/2*1/6*1/4
V=1/48 cubic ft
