Question

help me friends.... Plz

Answer 1

the spd of bot is 15km/hr

let the speed of river is x km/hr

now it travel 30 km upstrem and down stren

therefore upstream = (x-15)km/hr

downstream=(x+15)km/hr

it travels both distance in 4hr30min=4.5hr

therefore

30/(x-15) + 30/(x+15) =4.5

now take lcm and solve it