<span>In order to find the standard deviation, we first have to calculate the mean (average) of the numbers. To get this we add all the numbers together and then divide by 12 since there are 12 numbers. The mean = 782. Next, we take each number and subtract the mean, taking the result and squaring it. For this we get: 6724, 2209, 10404, 11664, 729, 1764, 12544, 9, 529, 71824, 1444, 1024. Now we sum all of these up and take the average by dividing the sum by 12. Doing this we get 120868/12=10072. The last step is the take the square root of that number to get the standard deviation. The final result is 100.</span>
Distance<-------------300--------------><-------------------x----------------->
⊕---------------------------------⊕--------------------------------------⊕ Express Freight Overtaking point
Speed 55 speed 30
Let x be the distance travelled by Freight until the point of overtaking
Time = Distance/Speed, then:
Time (freight) = Distance (fright)/Speed (freight) And
Time (Express) = Distance (Express)/Speed (Express).
Now plug in the relative number:
Time (freight) = x/30 and Time (express) = (x+300)/55. But note that both times are equal, then:
x/30 = (x+300)/55 OR (x÷30 = (x+300)÷55) [Answer C]
Now let's find the distance x. Cross multiplication;
55x= 30(300+x) →55x = 9,000 + 30x
55x - 30x = 9,000 → 25x = 9,000 and x = 9,000/25 = 360 miles
Time needed for Freight to travel 360 m = 360/30= 12 Hours
Time needed for Express to travel (300+360) m = 660/55= 12 Hours
As you see, it's the same time of 12 hours
Don't forget that Distance = Speed x time or time = Distance/Speed, etc.
Answer:
y = 6,350 + 392x
Step-by-step explanation:
One way of doing this is to write the equation of ratios (15 screwdrivers / 45 screwdrivers) = ($300 / x). Solve this equation for x. To do this, you might try multiplying both sides of this equation by x to eliminate fractions.
Another way is to obtain the unit cost of each screwdriver and then multiply the result by 45 screwdrivers.
