B i cant really tell how because thats hard for me to do but it is b
Answer:
<h3><u>Let's</u><u> </u><u>understand the concept</u><u>:</u><u>-</u></h3>
- Here 12 is 90% of a number.
- So we can say that 90% of That number is 12 .
- In this way we can get the the number
<h3><u>Solution</u><u>:</u><u>-</u></h3>
Let,
the number=x
<h3>According to the question ,</h3>


- We know 90%=90/100
- so add it




- Now use cross multiplication method








- Answer will come in decimals so we take approximate value.




The number is 13.
Given conditions are :
In 1980's, a typical middle-income household earned= $34,757
In 2009, a similar middle-income household earned= $38,550
And we have to find relative increase in income for these households from 1980 to 2009.
So first we will find the total increase in amounts.

Relative increase = 
= 10.91% or rounding it off we get approx 11%.
Hence, the answer is 11%.
4. 42,
Since Q1 is the first part of the box plot, and on the graph states
42
So this is going to be an exponential equation, which the format is

, in which a is the initial value and b is the growth/decay rate.
In this case, a is going to be 340,000 and b is going to be 107%, or 1.07, since the population is going to be increasing by 7% and the equation is now

.
Now replace x with 12 and solve.

Solve

, and then if you don't round that answer and multiply it with 340000 you get

.