Answer:
100 km/hr
Step-by-step explanation:
First Leg:
Speed = 60 km/h
Time = 30 min = 0.5 h
1st leg distance = speed x time = 60 km/hr x 0.5hr = 30 km
Second Leg:
Distance remaining = 80 km - 30 km = 50 km
Time = 30 min = 0.5 h
speed = distance / time = 50 / 0.5 = 100 km/hr
f = (f1 f2) / (f1 + f2)
f(f1 + f2) = f1 f2
f f 1 + f f 2 = f1 f 2
f1 f2 - f f2 = f f1
f2 (f1 - f) = f f1
f2 = (f f1) / (f1 - f) <==== solution
1 = sin²0 + cos²0
sin²0 = 1 - cos²0
sin²0 = 1 - 11/36
sin²0 = 25/36
sin 0 = 5/6 or -5/6
In the first quadrant, the values for sin, cos and tan are positive.
sin0 = 5/6
