You can
put this solution on YOUR website!d = distance the boat travelled.
boat travels for 2 hours against a 4 km/h current.
the whole trip took 5.5 hours which means the boat drifted back for 3.5 hours.
distance the boat travels against the current is equal to:
d = (b-4)*2
distance the boat drifts with the current is equal to:
d = (4)*3.5 = 14 miles
since the distance getting to the point where the boat broke down and getting back is the same distance, the formula for the boat getting to that point becomes:
14 = (b-4)*2
remove parentheses to get:
14 = 2b-8
add 8 to both sides to get:
2b = 22
divide both sides by 2 to get:
b = 11
Speed of the boat should be 11 miles per hour.
plug into the original equations to confirm this value is good.
first equation is boat getting to the breakdown point:
(b-4)*2 = d
replace d with 14 and b with 11 to get:
(11-4)*2 = 14 becomes: 7*2 = 14 becomes 14 = 14 confirming equation 1 is true.
second equation is boat drifting back to the starting point:
d = 4*3.5 becomes:
14 = 4*3.5 becomes 14 = 14 confirming e4quation 2 is true.
values look good.
speed of the boat in still water before breaking down is 11 miles per hour.
basic formula used is:
rate * time = distance
