You bought a car for $20,000$20,000. you have owned it for one year, and it is now worth $16,000$16,000. what is the percent decrease in your car's value?

The right answer is 20%.

Step-by-step explanation:

To resolve this question, we can use the "rule of three."

the rule of three tell us=

a-------------->b

c-------------->d

when we know the values for a,b and c; and we want to know the value of d we can use the next formula:

d=  

so in this case, we have:

20000--------->100% (is 100% cause is the total cost of the car)

16000 ---------> x         (we're going to call x to the value we don't know, and we want to know; we need to put the same values in the same part, in this example, we placed the costs of the car in the left and the percent in the right.

now using the formule we have:

= 80%

now we know the percent of the 16000, which means that 16000 is 80% of 20000.

the last step to know the decrease is subtract

20000-16000=4000

so

100%-80%=20%

the car's cost decrease  was 4000 what in percent is 20%