A boat goes 30 km upstream and 44km downstream in 10 hrs. On 13 hrs it can go 40 km upstream and 55 km downstream . Determine the speed of stream and the speed of the boat .
Answers
Answer:
Look at explaination so you understand (-:
Step-by-step explanation:
All you need to do is divide the amounts to get a total for both the boat and the stream. so if the boat can go 44 km downstream in ten hours then it goes 4.4 km downstream an hour. If it goes 30 km upstream in ten hours than it goes 3km upstream an hour. Just follow this process and you should be good!
Answer
Speed of boat in still water =x
Speed of stream =y
⇒ Speed of boat upstream =x−y
Speed of boat downstream =x+y
Thus,
x−y30+x+y44=10
Let x−y1=a and x+y1=b
So we have,
30a+44b=10 ... (1)
Similarly,
40a+55b=13 ... (2)
Multiplying (1) by 4 and (2) by 3, we get
120a+176b=40 ...(3)
120a+165b=39... (4)
Subtracting (4) from (3), we get
b=111
⇒x+y=11
Putting b=111 in (1), we get
30a+4=10
a=51
⇒x−y=5