Answer:
1200
Step-by-step explanation:
We’ll need a number that is evenly dividable by all three values: 8,12 & 15. We can develop the generic common multiple by multiplying all three numbers and get 1440. But is that the smallest common multiple? The quick and dirty way to factor the number is to divide it by it’s various elements and see what works. In this case 1440/12=120 which is the smallest common multiple of the three numbers. The smallest length is therefore 120.
In order to find how many bricks just divide (120x120x120)/(8x12x15)=1200 bricks
Answer:
The value of the test statistic is z = -0.877.
Step-by-step explanation:
Testing the difference in mean time spent on housework between husbands and wives.
At the null hypothesis, we test if there is no difference, that is, the subtraction of the means is 0:

At the alternate hypothesis, we test if there is a difference, that is, the subtraction of the means is different from 0.

The test statistic is:

In which X is the sample mean,
is the value tested at the null hypothesis, and s is the standard error.
0 is tested at the null hypothesis:
This means that 
For the wives the mean was 7 hours/week and for the husbands the mean was 4.5 hours/week. The standard deviation of the differences in time spent on house work was 2.85.
This means that 
What is the value of the test statistic for testing the difference in mean time spent on housework between husbands and wives?



The value of the test statistic is z = -0.877.
Answer:
b) 9
Step-by-step explanation:
9 squared + 40 squared = 41 squared, which follows Pythagorean theorem.