I think every 6 hours would be correct
Speed= distance/time
Speed= 170/230
Speed=0.74 m/s
Distance of lake a is 200 km at 20 degree north of east
distance between lake a and b is 230 km at 30 degree west of north
now the distance between base and lake b is given as

given that




now the total distance is


now the magnitude of the distance is given as


also the direction is given as


<em>so it is 277.4 km at 74.7 degree North of East</em>
Answer:
The speed of meteoroid is 21.61 km/s in south-east.
Explanation:
Given that,
A meteoroid is traveling through the atmosphere at 18.3 km/s. while descending at a rate of 11.5 km/s it means 11.5 km/s in south.
We need to draw a diagram
Using Pythagorean theorem




Hence, The speed of meteoroid is 21.61 km/s in south-east.