First, turn the fractions into mixed numbers.
21/4 - 27/8
Then. make the denominators the same.
4 * 2 = 8
21 * 2 = 42
42/8 - 27/8
42 - 27 = 15
15/8
15/8 = 1 7/8
Answer:

Step-by-step explanation:
Since the population standard deviation
, is known, we use the z confidence interval for the mean.
This is given by:

For a 95% confidence interval we use
.
It was also given that:
,
and 
Let us substitute the values to get:


<u>Interpretation:</u>
We can say with 95% confidence that the interval between 1463.3 and 1580.7 SAT scores contains the population mean based on the sample 125 SAT scores.
Answer:
9ab+3a
Step-by-step explanation:
(2a+a)(3b+1)=(3a)(3b+1)
3a(3b+1)
=(3a×3b)+3a×1
=9ab+3a
Time it takes you to complete the walk
You are given the area of both cupboards.
The total area would be found by adding the two areas together:
3a^2 − 5y + 15 + 4a^2 + 5y + 5
Combine like terms:
3a^2 + 4a^2 = 7a^2
-5y + 5y = 0y
15 +5 = 20
The area of both cupboards would be 7a^2+20