1w-4= 4-1w
+1w +1w
——————
2w-4=4
+4 +4
—————
2w=8
———
2. 2
w= 4
Recall your d = rt, distance = rate * time.
now, if the boat has a speed of say "b", and the current has a speed of say "c", when the boat is going upstream, is not really going "b" fast, is going " b - c " fast, because the current is eroding speed from it, going upwards.
And when the boat is going downstream, is not going "b" fast either, because the current is now adding to speed to it, so is really going " b + c " fast.
The time it took one way, is the same time it took back, 4 hours each way.
thus

what's the speed of the boat? well, 5 + c = b.
Answer:
s= 30000+1500x
Step-by-step explanation:
Given data
Le the number of years be x
His salary for the first year is $30,000
5% of $30,000
=5/100*30000
= 0.05*30000
= $1500
Hence for x years the salary can be described as
s= 30000+1500x