Answer:
72 yellow balls
Step-by-step explanation:
80% of 90 is (0.80*90) = 72 yellow balls.
Answer for number 4 is
hour.
Step-by-step explanation:
Maximum hour spent for all homework (English homework + math homework) is 2 hours.
Let us assume the hours spent for English homework be 'e'.
It is given that:
(Hours spent for math homework) = 2 × (Hours spent for English homework)
Hours spent for math homework = 2 × e = 2e
Total hours spent = (Hours spent for math homework) + (Hours spent for English homework)
Total hours spent = 2e + e = 3e
2 = 3e
3e = 2
∴ e = 
Therefore number of hours spent on English homework is equal to
hours.
Answer:
-12y + 20
Step-by-step explanation:
First, you simplify each term:
apply the distributive property:
4 - 5y - 2 (3.5y) - 2 x -8
Multiply 3.5 by -2:
4 - 5y - 2 (3.5y) - 2 x -8
Multiply -2 by -8:
4 - 5y - 7y +16
Next, we simplify by adding terms:
Add 4 + 16:
-5y - 7y + 20
Subtract 7y from 5y:
-12y + 20
Hence the simplified form is -12y + 20
480,000,000 (480 million)
The area formula of a circle is
× π.
With that being said, we can solve both problems!
Starting with part A:
-The radius we know is 21cm. From there, we can substitute in our formula with the new value.
x π
From there, we can square our radius:
(21 x 21) x π
(441) x π
And finally, we can multiply by pi to get our answer.
(441) x π
1385.44236023
Which rounded to the nearest tenth is 1385.4. Therefore, the area of the porthole is 1385.4 centimetres.
The second part can be followed with the same process, hopefully you understand the concept enough to where you're comfortable solving problems like this on your own. Feel free to reach out if you have any further trouble!
<em>Hope this helped! :)</em>