Answer:
Option C is correct.
roots of the given equation , 
Step-by-step explanation:
Given the equation: 
We can write this equation as:

A quadratic equation is in the form of
......[1] where a,b ,c are the coefficient and x is the variable,
the solution of the equation is given by;

On comparing given equation with equation [1] we get;
a = 3 , b = -4 and c =10
So, the solution of the given equation is given by;

or

or
[∴
Simplify:

therefore, the roots of the given equation are; 
V=Vo (1-r/100)^n
V=46900(1-3.2/100)^8
V=46900(96.8/100)^8
V=46900*(.968)^8
V=36155.61
V=36155(approx)
answer: 16 minutes
Step-by-step explanation:
0.8 would mean 80% of 20minutes.
80/100 × 20 =
=1600/100
=16 minutes