From the given function modeling the height of the ball:
f(x)=-0.2x^2+1.4x+7
A] The maximum height of the ball will be given by:
At max height f'(x)=0
from f(x),
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
thus the maximum height would be:
f(3.5)=-0.2(3.5)^2+1.4(3.5)+7
f(3.5)=9.45 ft
b]
How far from where the ball was thrown did this occur:
from (a), we see that at maximum height f'(x)=0
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
This implies that it occurred 3.5 ft from where the ball was thrown.
c] How far does the ball travel horizontally?
f(x)=-0.2x^2+1.4x+7
evaluationg the expression when f(x)=0 we get:
0=-0.2x^2+1.4x+7
Using quadratic equation formula:
x=-3.37386 or x=10.3739
We leave out the negative and take the positive answer. Hence the answer 10.3739 ft horizontally.
With the sum of 99, we will get 50 pairs whole numbers. Why?
Let’s start with
0+ 99
1 + 98
2 + 97
3 + 96
4 + 95
5 + 94
6 + 93
7 + 92
8 + 91
9 + 90
10 + 89
………
……..
43 + 49
44 + 50
Therefore, if you’re going to count all pairs of whole number, you will get 50 pairs of whole number with the sum of 99.
Hope this helps!
R(t)=10t+20. This shows the first 20 pesos, and the additional 10 pesos for every hour. Hope this helps.
The
formula
, where r! is 1*2*3*...r
is the
formula which gives us the total number of ways of forming groups of r objects out of n objects.
for
example, given 10 objects, there are C(10,6) ways of forming groups of 6, out
of the 10 objects.
<span>Thus, there are C(6, 3) many ways of forming different triples out of 6.</span>

Answer: A.20