Explanation:
Pair 1 is true if Jeff's monthly income is $600/20% = $3,000.
Pair 2 is true if Jeff's monthly income is $1200/10% = $12,000.
Both pairs can be true if Jeff's monthly income increased by a factor of 4 in the 20 years from 1990 to 2010.
Obviously, Jeff spent more on housing in 2010. (Fortunately for Jeff, that larger expenditure was a smaller fraction of his income.)
Answer: 
Step-by-step explanation:
<h3>
The complete exercise is: " A circle has a radius of 6. An arc in this circle has a central angle of 330 degrees. What is the arc length?"</h3><h3>
</h3>
To solve this exercise you need to use the following formula to find the Arc lenght:

Where "C" is the central angle of the arc (in degrees) and "r" is the radius.
In this case, after analize the information given in the exercise, you can identify that the radius and the central angle in degrees, are:

Therefore, knowing these values, you can substitute them into the formula:

And finally,you must evaluate in order to find the Arc lenght.
You get that this is:

Answer:
There are 650 cannonballs
Step-by-step explanation:
If you look closely in the picture, you can see that:
- 1st row has 1 ball
- 2nd row has 4 balls
- 3rd row has 9 balls
- 4th row has 16 balls
etc. etc.
We can see that the number of balls is the square of the row number. There are a total of 12 rows. So, rest of the rows has:
- 5th row has 25 balls
- 6th row has 36 balls
- 7th row has 49 balls
- 8th row has 64 balls
- 9th row has 81 balls
- 10th row has 100 balls
- 11th row has 121 balls
- 12th row has 144 balls
If we add up all those, we get total number of balls:

There are 650 cannonballs
(26/25) x (15/28) x (8/39)
Divide top and bottom by 3 :
(26/25) x (5/28) x (8/13)
Divide top and bottom by 5 :
(26/5) x (1/28) x (8/13)
Divide top and bottom by 4 :
(26/5) x (1/7) x (2/13)
= 52 / 455 = 0.11429... (rounded)
Follow these steps:
-8.4b - 4.2 = 12.6
Add 4.2 on both sides:
-8.4b = 16.8
Divide by -8.4 on both sides to give you the final answer of:
b = -2
So you're answer is indeed correct! Hope this helps and that the steps are clear enough!