Every week, Fred deposits $84 into his savings account, which is 20% of his weekly income. How much income does Fred make each week? $505
$480
$420
$510

Step-by-step explanation:

if 84 dollars represents 20% of his income

?represents 100%

84*100/20=420 dollars

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50