Hello, asnxbbyx113!

Another approach to #2 . . .

The man walks north from at 5 ft/sec.

Since he has a 5-minute (300-second) headstart.

. . he has already walked: feet.

In the next seconds, he walks feet more to

The woman walks south from at 4 ft/s.

In the next seconds, she walks feet to

The diagram looks like this: Code:

A *
| *
5t| *
| *
+ *
| * R
1500| *
| *
P *---------------*-------* Q
: * |
4t: * |4t
: * |
C + - - - - - - - - - - - * B
: 1300 :

The distance between them is:

From the right triangle , we have:

. .

Differentiate: .

. . and we have: .

"20 minutes after the woman starts walking" means: seconds.

. . Plug it in and simplify . . .