jack ran 1.5 kilometers on the treadmill, then walked 475 meters before running another 2.5 kilometers how many kilometers did jack do in all

We need first consider what data we have available:
a = run 1.5km
b = then run 2.3km
c = walk 475m
x = a + b + c = how many km he done on treadmill
before we go anywhere, we need to unify the units, we need to change meters to fraction of kilometers, kilo meant 1000, therefore:
1km = 1000m
475m / 1000m = 0.475km
now we can substitute:
x = a + b + c = 1.5km + 2.3km + 0.475km = 4.275km
we can round that up to first decimal point and then:
4.275km = 4.3km
answer is then:
jack done on the treadmill 4.275km or rounded up 4.3km

The answer is option c.