Question

Question #53981

Answer 1

Laura and Brent paddle at 1.75 miles per hour in still water

Explanation:

Assume that Laura and Brent paddle at a constant speed

let `x` be their paddling speed
let `y` be the speed of the river

up-river
`6/4 = x-y`

down-river
`6/3 = x+y`

to get rid of the `y` term add the two equations together
`3.5 = 2x`

and rearrange
`x = 1.75`