SOLUTION: A boat traveled 210 miles in 10 hours against the current. The boat then returned with the current in 6 hours. What were the speeds of the boat and of the current?

Algebra ->  Linear-equations -> SOLUTION: A boat traveled 210 miles in 10 hours against the current. The boat then returned with the current in 6 hours. What were the speeds of the boat and of the current?      Log On


   

Question 837616: A boat traveled 210 miles in 10 hours against the current. The boat then returned with the current in 6 hours. What were the speeds of the boat and of the current?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
boat speed =x mph
current speed =y mph
against current 10 hours
with current 6 hours

Distance against 210 miles distance with 210 miles
t=d/r against current -
210.00 / ( x - y )= 10.00
10.00 ( x - y ) = 6.00
10.00 x - 10.00 y = 210.00 ....................1

210.00 / ( x + y )= 6.00
6.00 ( x + y ) = 210.00
6.00 x + 6.00 y = 210.00 ...............2
Multiply (1) by 3.00
Multiply (2) by 5.00
we get
30.00 x + -30.00 y = 630.00
30.00 x + 30.00 y = 1050.00
60.00 x = 1680.00
/ 60.00
x = 28.00 mph

plug value of x in (1) y
10.00 x -10.00 y = 210.00
280.00 -10.00 -280.00 = 210.00
-10.00 y = 210.00
-10.00 y = -70.00 mph
y = 7.00
boat speed 28.00 mph
current speed 7.00 mph

m.ananth@hotmail.ca