Question

Tell me the answer of this question fast....​

Answer 1

Answer:

3 km/hr

Step-by-step explanation:

let speed of water=x

speed downstream=9+x

upstream=9-x

time down stream t1=12/9+x

time down stream t2=12/9-x

t1+t2=12/9+x+12/9-x=3

4/9+x+4/9-x=1

4(9-x+9-x)=(9-x)(9+x)

4*18=81-x2

x2=81-72

x2=9

x=3 km/hr

Answer 2

Here, speed cannot be negative

Thus we take positive sign.

Hope you understand