Answer:
hmmm
Step-by-step explanation:
Let's make,
mechanic #1's rate = x
mechanic #2's rate = y
* Their rate is dollars per hour ($/hr)
mechanic #1 worked for 20 hours (hr × $/hr = $)
20x = money earned by mech#1
and mechanic #2 worked for 5 hours
5y = money earned by mech#2
together they charged a total of $1150. So the amount of money earned by both mechanics.
20x + 5y = 1150
the sum of the two rates was $95 per hour.
x + y = 95
which means
x = 95 - y
plug (95 - y) in for "x" in the other equation to get everything in terms of one variable.
20(95 - y) + 5y = 1150
solve for y
1900 - 20y + 5y = 1150
1900 - 15y = 1150
-15y = 1150 - 1900
-15y = -750
y = -750/-15
y = 50 $/hr
Now use this to solve for x
x + y = 95
x + 50 = 95
x = 95 - 50
x = 45 $/hr
mech#1 charged 45$/hr
mech #2 charged 50$/hr
The probability that the next 4 winners will all be 7th grade students is 3/4
Answer:
When sampling from a population, the sample mean will: be closer to the population mean as the sample size increases.
Step-by-step explanation:
The sample mean is not always equal to the population mean but if we increase the number of samples then the mean of the sample would become more and more closer to the population mean.
Usually the population size is very huge that is why we select a random sample from the population, care must be taken to ensure randomized sampling otherwise results would not be accurate. After that we have to make sure that the number of samples are enough for the given population size. The number of samples depends upon the shape of the population. If the population is normal than according to central limit theorem, a less number of samples would be enough to ensure normal distribution of sampling mean, otherwise a greater sample size will be required.
Answer:
C
Step-by-step explanation:
Using Pythagoras' identity in the right triangle
The square on the hypotenuse is equal to the sum of the squares on the 2 other sides, that is
x² + 6² = 17²
x² + 36 = 289 ( subtract 36 from both sides )
x² = 253 ( take the square root of both sides )
x = 
→ C
