Question

A fisherman can

Answer 1

Answer:

4 [miles].

Step-by-step explanation:

1) the condition 'the entire trip took 5 hours' can be written as (where t_us - time spent upstream, t_ds - time spent downstream)

$t_{us}+t_{ds}=5;$

2) but the distance [D] upstream is equal the distance downstream, then the condition above can be written:

$\frac{D}{V_{us}} +\frac{D}{V_{ds}} =5; \ (V_{us}-rowing \ upstream,V_{ds}-rowing \ downstream);$

3) finally,

$D=\frac{5V_{us}*V_{ds}}{V_{us}+V_{ds}};$

D=5*4/5=4 [miles].