Answer:
a) 72.25sec
b) 6.25secs
c) after 10.5secs and 2 secs
Step-by-step explanation:
Given the height reached by the rocket expressed as;
s(t)= -4t^2 + 50t - 84
At maximum height, the velocity of the rocket is zero i.e ds/dt = 0
ds/dt = -8t + 50
0 = -8t + 50
8t = 50
t = 50/8
t = 6.25secs
Hence it will reach the maximum height after 6.25secs
To get the maximum height, you will substitute t - 6.25s into the given expression
s(t)= -4t^2 + 50t - 84
s(6.25) = -4(6.25)^2 + 50(6.25) - 84
s(6.25) = -156.25 + 312.5 - 84
s(6.25) = 72.25feet
Hence the maximum height reached by the rocket is 72.25feet
The rocket will reach the ground when s(t) = 0
Substitute into the expression
s(t)= -4t^2 + 50t - 84
0 = -4t^2 + 50t - 84
4t^2 - 50t + 84 = 0
2t^2 - 25t + 42 = 0
2t^2 - 4t - 21t + 42 = 0
2t(t-2)-21(t-2) = 0
(2t - 21) (t - 2) = 0
2t - 21 = 0 and t - 2 = 0
2t = 21 and t = 2
t = 10.5 and 2
Hence the time the rocket will reach the ground are after 10.5secs and 2 secs
To multiply it by itself three time eg 2x2x2
The probability is 1/1024.
Each tetrahedron has a 1/4 chance of landing on 3, since there are 4 sides and only one of them is marked 3.
Each tetrahedron roll is independent, since no roll is affected by another.
This means we multiply the probabilities:
1/4(1/4)(1/4)(1/4)(1/4) = 1/1024
Okay, so we know a number of students and the amount of girls as a bracket. So what we have to do now is multiply them with each other.
28 *4/7 = 16
So there are 16 girls in Mr. Chang´s class.
You can also determine the boys by - the students with the girls:
28-16=12 boys
Have a nice day :D
Answer:
D.Transitive property of equality
Step-by-step explanation:
We are given that segment JK is parallel to segment LM
We have to prove 
We have to find which option correctly justifies the statement 4 of the two - column proof.
1.Statement : JK is parallel to segment LM
Reason: Given
2.
Reason: Vertical angles theorem
3.
Reason:Corresponding angles theorem
4.
Reason: Transitive property of equality.
If a=b and b=c then a=c
Hence, option D is true.
