solve the following problem please

Question

In a particular classroom with 20 students, the rate y at which a rumor spreads is related to the number of people x who have heard the rumor according to the bexpression y= 0.3x(20-x). Determine how many people will have heard the rumor when the spread of the rumor is at its greatest

Answer 1

y= 6x - 0.3x²

y = x (6 - 0.3x)

 

x ∈ { 0, 20 }

 

When 20 student has heard the rumor it has spread at the greatest rate.