Answer: A; 6.3%
Step-by-step explanation:
Problem 1
For the first problem, we first want to find y so that we can plug it into the expression.
We can use elimination method for the system of equations to solve.
3x+3y=21
3x-y=5
We subtract both equations to eliminate x.
4y=16 [divide both sides by 4]
y=4
Now that we know y, we can plug it into the expression.
[divide]
[subtract]
We know that the answer is A.
--------------------------------------------------------------------------------------------------------
Problem 2
For the second problem, we need to know how to calculate percent error. The formula for precent error is 
. We know that the exact value is 80 because the buyer was supposed to given 80. 75 is the measured value because that was what the buyer was given.
[subtract]
[solve absolue value]
[divide]
[multiply]
Since the problem said to round to one decimal place, we know that the answer is 6.3%.
x = child tickets
y = adult tickets
x + y = 141
5.60x + 9.30y = 974.60
y = 141 - x
5.60x + 9.30 ( 141 - x ) = 974.60
5.60x + 1311.3 - 9.30x = 974.60
-3.70x + 1311.3 = 974.60
-3.70x = 974.60 - 1311.3
-3.70x = -336.7
x = 91
91 child tickets were sold that day
Answer:
The number of bacteria after 
will be 
Step-by-step explanation:
Given the initially 30 bacteria present in the culture.
Also, the number of bacteria got doubled every hour.
So, using the equation
Where 
is number of bacteria after 
hours.
is bacteria present initially.
is the common ration, in our problem it is given that bacteria doubles every hour. So, 
And is the number of hours. In our problem we need amount of bacteria at the end of hours. So, 
Plugging values in the formula we get,
So, number of bacteria after will be
Answer:
The larger of the two is 44.67
Step-by-step explanation:
let the first number=x
let the second number=y
We can derive a system of equations using the mathematical statements
Their sum is 33:
x+y=33( call this equation 1)
Sum of first number and four times the second is -2:
x+4y=-2(call this equation 2)
Since the integer coefficients of x in both equations are the same we can quickly subtract one from the other to eliminate it
For this explanation, I choose to subtract equation 1 from 2
(x+4y=-2)-(x+y=33)=3y=-35
y=-35/3
Now plug in the value of y into any equation for that of x. Say we plug into equation 1
x+(-35/3)=33
x-35/3=33( multiply through by 3)
3x-35=99
3x=99+35
3x=134
x=134/3
Therefore,x=134/3 or 44.67 and y=-35/3 or -11.67
Answer:
D. No solution because the lines are parallel
Step-by-step explanation:
Hope this helps you :)
