In order to answer the question, you need to know the area of a circle.
Area = pi * r^2
Area = 3.14 * (100/2) ^ 2
Area = 3.14 * 50^2
Area = 7850 mils^2 = 0.00785 in^2
(i) speed = distance / time
so time = distance / speed
here we have
time t = 1080/x hours
(ii) return flight time = 1080 / (x + 30) hours
(a) 1080/x - 1080/(x + 30) = 1/2
Multiplying through by the LCD 2x(x + 30) we get:-
1080*2(x + 30) - 2x*1080 = x(x+30)
2160x + 64800 - 2160x = x^2 + 30x
x^2 + 30x - 64800 = 0
(b) factoring; -64800 = 270 * -240 ans 270-240 = 30 so we have
(x + 270)(x - 240) = 0 so x = 240 ( we ignore the negative -270)
So the speed for outward journey is 240 km/hr
(c) time ffor outward flight = 1080 / 240 = 4 1/2 hours
(d) average speed for whole flight = distance / time
Time for outward journey = 4.5 hours and time for return journey = d / v
= 1080 / (240+30) = 4 hours
Therefore the average speed for whole journey = 2160 / 8.5 = 254.1 km/hr
Answer:
Step-by-step explanation:
D is your answer
$56.18
V=40L
.005*40=.2
40-.2 * 7 = 38.6 L after 1 week
