Answer:
the object is in the air on the time interval (0.24 sec, 6.51 sec)
Step-by-step explanation:
The object is 'in the air' for all t such that h> 0. We need to find the roots of h = -16t^2 + 108t - 25 = 0. From the graph we see that both t values are positive. Once we find them, we subtract the smaller t from the larger t, which results in the length of time the object is in the air.
Use the quadratic formula to find the roots of h(t). The coefficients of t are {-16, 108, -25}, and so the discriminant b^2 - 4ac is
108² - 4(-16)(-25) = 11664 - 1600 = 10064, whose square root is 100.32.
Then the quadratic formula x = (-b ± √[b² - 4ac)/(2a) becomes
-108 ± 100.32 108 ± 100.32
t = ---------------------- = --------------------- = 3.375 ± 3.135
2(-16) 32
or t = 6.51 or t = 0.24 (both times expressed in seconds).
So, again, the object is in the air on the time interval (0.24 sec, 6.51 sec)
<span>
<span>Speed
is calculated as distance covered, divided by the time taken to cover that
distance. In this case, the sales person covered 50KM in 45minutes (which can
also be expressed as 3/4 hours). To calculate the speed he used to cover this
distance, we divide the distance covered by the time taken. So 50km/3/4hours.
This gives us 66.67km/hr. In order to calculate the amount of time the
salesperson used to travel from the office to the sales person, we calculate
as follows 250km/66.67km/hr. This gives us a total of 3.75 hours or 3 hours 45 minutes.</span></span>
Answer:
20%
Step-by-step explanation:
20% of 50 is 10, and they spent 10 hours walking.
$63.99 *0.85=$54.40 ($54.3915)<span> rounded = Sale Price
$63.99-54.40= </span> $9.60 $9.59 rounded = Discount
