Answer:
20+14
Step-by-step explanation:
Math
<span>6 km × 1 hour/(b-4 km) = 12 km × (1 hour/(b+4 km)
6/(b-4) hours = 12/(b+4) hours
6(b+4) = 12(b-4)
6b + 24 = 12b - 48
72 = 6b
b = 12
The boat's speed in still water is 12 km/hour.</span>
I think the correct answer from the choices listed above is the second option. Combining probabilities is a function of mutually exclusive events. Joint probability<span> is a measure of two events happening at the same time, and can only be applied to situations where more than one observation can be occurred at the same time.</span>