An experience bricklayer can construct a small wall in 3 hours. An apprentice can complete the job in 5 hours. Find how long it
1 answer:
Answer:
Step-by-step explanation:
If the bricklayer can construct the wall in its entirety in 3 hours, then he can get 1/3 of the job done in an hour.
If the apprentice can get the whole job done in 5 hours, then he can get 1/5 of the job done in an hour. If they both work together on said job, the equation is
and now we solve for x. Multiply everything by the LCM to get rid of the fractions. That would be 15x:
and doing that gives us
5x + 3x = 15 and
8x = 15 so
x = 1.875 hours which is 1 7/8 hours which is also 1 hour and 52 1/2 minutes.
You might be interested in
Answer:
Step-by-step explanation:
Assuming conditions are met, the formula for a confidence interval (CI) for the difference between two population proportions is where
and
are the sample proportion and sample size of the first sample, and
and
are the sample proportion and sample size of the second sample.
We see that and
. We also know that a 98% confidence level corresponds to a critical value of
, so we can plug these values into the formula to get our desired confidence interval:
Hence, we are 98% confident that the true difference in the proportion of people that live in a city who identify as a democrat and the proportion of people that live in a rural area who identify as a democrat is contained within the interval {-0.2941,-0.0337}
The 98% confidence interval also suggests that it may be more likely that identified democrats in a rural area have a greater proportion than identified democrats in a city since the differences in the interval are less than 0.