Question

using two variable only solve the following :speed of the boat in down stream is 15 km per hour and in up stream is 5 km per hour. find the speed of boat in still water. by using only two variable. the answer is 10 km per hr. but i font know the solution...​

Answer 1

Answer:

10 km/hr

Step-by-step explanation:

Let  speed of the boat be x and speed of the stream be y

Express speed upstream and downstream as:

• Speed downstream = x+y
• Speed upstream = x-y

And add their values:

• x+y=15
• x-y=5

Add up these 2 equations:

• x+y+x-y=15+5
• 2x=20
• x=10

Hope it helps