Answer:
The equation for the price, as a function of time in hours is:
P(x) = 20*x for 0 ≤ x ≤ 2
P(x) = 40 + 10*(x - 2) for 2 ≤ x
Now, we want to evaluate this function in 40 mins.
we know that 1 hour = 60mins.
Then 40 mins = (40/60) hours = 0.67 hours.
Then we input this in our function, and because this is smaller than 2, we use the first piece of our function:
P(0.67) = 20*0.67 = 13.4
So in 40 mins, the charge will be 13.4 pesos.
H represents the height of the ball at a given time, symbolised as t.
Thus, we just need to find when h = 0 so that we find when it hits the ground.
0 = -4.9t² + 19.6t + 58.8
0 = 4.9t² - 19.6t - 58.8
0 = 49t² - 196t - 588
0 = t² - 4t - 12
0 = (t - 6)(t + 2)
So, t = 6 or -2, but t ≠ -2, since time cannot be negative in this instance.
Hence, at 6 seconds, the ball will strike the ground.
Quadratic equation: ax² + bx + c =0
x' = [-b+√(b²-4ac)]/2a and x" = [-b-√(b²-4ac)]/2a
6 = x² – 10x ; x² - 10x -6 =0
(a=1, b= - 10 and c = - 6
x' = [10+√(10²+4(1)(-6)]/2(1) and x" = [10-√(10²+4(1)(-6)]/2(1)
x' =5+√31 and x' = 5-√31
