Answer:
A: 270 ,':)
Step-by-step explanation:
The rate charged per hour by each mechanic was: x = 75 $ / hr and y = 115 $ / hr.
<h3>What is a system of equations?</h3>
A system of equations is two or more equations that can be solved to get a unique solution. the power of the equation must be in one degree.
Given;
The first mechanic worked for 20 hours, and the second mechanic worked for 15 hours.
Together they charged a total of $3225.
For this case we have the following variables:
x be the amount of $ / hr that the mechanic obtains 1.
y be the amount of $ / hr obtained by mechanic 2.
An equation to express this would be:
x + y = 190
20x + 15y = 3225
Solving the system of equations we have:
20x + 15(190 -x) = 3225
20x + 2850 - 15x = 3225
5x = 375
x = 75
simililary
y = 190 - x
y = 115
Hence, the rate charged per hour by each mechanic was:
x = 75 $ / hr
y = 115 $ / hr
Learn more about equations here;
brainly.com/question/10413253
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Answer:
x=4
Step-by-step explanation:
Answer:
Step-by-step explanation:
This is a d = rt problem; but since it is linear, then proportions will work too. Set up the proportion with miles on top and hours on the bottom:
Then put the numbers in where they go, keeping in mind that miles goes with miles and hours goes with hours in the ratios, and that our unknown is time (hours):
and cross multiply to solve:
638x = 4466 so
x = 7 hrs
24 total marbles
6 are black
so you have a 6/24, reduced to 1/4 probability of picking a black one.
