Kali runs 10 laps around a track each day. Each lap around the track is 400 meters. How many days will it take kali to run a total of 12 kilometers?

Answer 1

This type of conversion, just as in Chemistry, can easily be handled by dimensional analysis (aka, the "unit factor method").

? days=12kmx(1000m/km)x(1lap/400m)x(1day/10laps)=3 days

Notice that all units cancel out except for the desired units of total days. This is the hallmark of the unit factor method for solving conversions.