Answer:
92 attendees had activity cards
Step-by-step explanation:
Let x be the number of students with activity cards. Then 130-x is the number without, and the total revenue is ...
7x +10(130 -x) = 1024
7x +1300 -10x = 1024 . . . . eliminate parentheses
-3x = -276 . . . . . . . . . . . . . collect terms; subtract 1300
x = 92 . . . . . . divide by 3
92 students with activity cards attended the dance.
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<em>Comment on the solution</em>
Often, you will see such a problem solved using two equations. For example, they might be ...
Let 'a' represent the number with an activity card; 'w' the number without. Then ...
- a+w = 130 . . . . the total number of students
- 7a +10w = 1024 . . . . the revenue from ticket sales
The problem statement asks for the value of 'a', so you want to eliminate w from these equations. You can do that using substitution. Using the first equation to write an expression for w, you have ...
w = 130-a
and making the substitution into the second equation gives ...
7a +10(130 -a) = 1024
This should look a lot like the equation we used above. There, we skipped the extra variable and went straight to the single equation we needed to solve.
Answer:
the length of the wall of the room = 11
Step-by-step explanation:
if it's a square room, area of each wall, floor and top are equal, so,
=》
=》
=》
so, length of wall of the room is 11 meters.
The expression to be simplified is: (9x^2 - 25) / (3x + 5)
We first factor the numerator: 9x^2 - 25 is a difference of two squares, (3x)^2 - (5)^2, so this can be factored into (3x + 5)(3x - 5).
Then the expression becomes (3x + 5)(3x - 5) / (3x+5), and the 3x + 5 term cancels out, leaving just 3x - 5 as the final answer.
Answer:
2/5
Step-by-step explanation:
Take the number of candy bars and divide by the number of students
2/5
Each will get 2/5 of a candy bar
Answer:
a) Binomial.
b) n=20, p=0.01, k≥2
The probability hat a package sold will be refunded is P=0.0169.
Step-by-step explanation:
a) We know that
- the defective probability is constant and independent.
- the sample size is bigger than one subject.
The most appropiate distribution to represent this random variable is the binomial.
b) The parameters are:
- Sample size (amount of clips in the package): n=20
- Probability of defective clips: p=0.01.
- number of defective clips that trigger the money-back guarantee: k≥2
The probability of the package being refunded can be calculated as: