Hello, jumpman!

This is just simple arithmetic, isn't it?

Rachel is running around a track at a constant speed of 1.4m/sec.

The 400m track is divided into equal lengths at points A, B, C, and D.

If Rachel starts at point M halfway between points A and B, and runs ccw,

after 30 minutes, at what point (A, B, C, or D) will she be closest?

The track is probably round or oval, but I'll make it square in my diagram. Code:

50 M 50
B*------*------*A
| |
| |
100 | | 100
| |
| |
| |
C*-------------*D
100

She runs at 1.4 meters per second,

. . or: .1.4 × 60 .= .84 meters per minute.

In 30 minutes, she runs: .30 × 84 .= .2520 meters

. . 2520 ÷ 400 .= .6, remainder 120

She runs six full laps, plus 120 meters beyond point M.

. . This puts her 70 meters past point B and 30 meters before point C.

Therefore, she is the closest to point C.