Answer:
18.7 years
Step-by-step explanation:
This is a compound interest problem and the following variables have been given;
Principal = 4000; this is the amount o be invested
APR = 9%; this is the compound interest to be earned
Accumulated amount = 20,000
We are required to determine the duration in years. We apply the compound interest formula;


The next step is to introduce natural logarithms in order to determine n;

The number of years required is thus 18.7 years
Area is supposed to be multiplied by 2.
Answer:
c
Step-by-step explanation:
Answer:
$57

Step-by-step explanation:
Given that:
Earnings per hour for washing cars = $9
Earnings per hour for walking dogs = $6
Number of hours for which car washing is done = 
Number of hours taken for walking dogs = 
Earnings for
hours for washing cars = Per hour earnings multiplied by number of hours = $9
Earnings for
hours for walking dogs = Per hour earnings multiplied by number of hours = $6
Total earnings by both = $(
)
Now, given that
Number of hours spent washing cars = 5 hours
Number of hours spent walking dogs = 2 hours
Therefore, total earnings by both = 9
5 + 6
2 = <em>$57</em>