The cost to join a gym includes a one-time membership fee, plus a monthly fee. John joined the gym and paid $325 for 6 months.Ab
1 answer:
We need to construct the system of equations in order to solve that problem. Let's denote one-time membership fee with x and monthly fee with y. Then we can write that John paid x+6y=325 and Abigail paid x+9y=475. Solving the system of equations 
, we find that x=25 and y=50. The monthly fee is 50 dollars.
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Answer:
180 pages
Step-by-step explanation:
Since her photocopy session is 25 pages per minute, the total number of pages photocopied in 4 hour session can be calculated as;
number of pages = time × speed
= (4 × 60) × 25
= 240 ×25
= 6000 pages
Thus, number of pages photocopied in 4 hours is 6000.
For every 100 pages, 3 would contain some type of printing error. The number of pages she expect with printing error during 4 hour session can be determined as;
= × 3
= 60 × 3
= 180 pages
The expected number of pages with printing error during 4 hour photocopying session is 180 pages.
Answer:
See the proof below.
Step-by-step explanation:
For this case we just need to apply properties of expected value. We know that the estimator is given by:
And we want to proof that
So we can begin with this:
And we can distribute the expected value into the temrs like this:
And we know that the expected value for the estimator of the variance s is , or in other way
so if we apply this property here we have:
And we know that so using this we can take common factor like this:
And then we see that the pooled variance is an unbiased estimator for the population variance when we have two population with the same variance.