It does not say simple or compound interest.
Simple interest is rarely used these days, so assume compound.
Use the standard formula:
future value = present value*(1+rate/n)^(nt)
n=number of times interest is compounded per year (=1)
t=number of years
Plugging values,
200=100(1.09)^t
1.09^t = 2
take log
t(log(1.09))=log 2
t=log(2)/log(1.09)=0.6931/0.08618=8.04 years.
$16.80 / 4 gallons = $4.20 per gallon
Answer:When a vertical line is placed across the plot of this relation, it intersects the graph more than once for some values of x. If a graph shows two or more intersections with a vertical line, then an input (x-coordinate) can have more than one output (y-coordinate), and y is not a function of x.
Step-by-step explanation: