Step-by-step explanation:
h(t) = -5t² + 20t + 18
this is a parabola (the curve an object follows when thrown up into the air and then falling back down).
and as such it will most likely have 2 solutions (one for when going up, and one for when falling back down again).
33 = -5t² + 20t + 18
15 = -5t² + 20t
-3 = t² - 4t
t² - 4t + 3 = 0
the solution of such a quadratic equation is
t = (-b ±sqrt(b² - 4ac))/(2a)
in our case
a = 1
b = -4
c = 3
t = (4 ±sqrt(16 - 4×1×3))/(2×1) = (4 ±sqrt(16-12))/2 =
= (4 ±sqrt(4))/2 = (4 ± 2)/2
t1 = (4+2)/2 = 6/2 = 3
t2 = (4-2)/2 = 2/2 = 1
the object reaches the height of 33 m first after 1 second (while going up), and then again after 3 seconds (while falling down again).
Answer:
there were 63,000L of water initially in the pool
Step-by-step explanation:
do 900L times the first 20 minutes to find out how much water was drained during the first 20 minutes and you get 18,000L drained
then, add 18,000L plus the rest of the 45,000L of water drained from the pool to get 63,000L of water intially in the pool
Answer:
106.68 centimeters.
Step-by-step explanation:
3.5 multiplied 12 is 42. 42 multiplied by 2.54 is equal to 106.68
Answer:
Step-by-step explanation:
A 99% confidence interval for the mean sodium content in Oriental Spice Sauce is,
First, compute t -critical value then find confidence interval.
The t critical value is,
The sample size is small and two-tailed test. Look in the column headed 
and the row headed in the t distribution table by using degree of freedom is,
d . f . =n-1
=170-1
=169
The t critical value is 2.605 .
A 
confidence interval for the mean sodium content in Oriental Spice Sauce is
