Sarah roller skates for 3 hours with a constant speed of 18mph and then for another 1 hour with a constant speed of 12mph. what distance did she go?

3 * 18 = 54 miles.

1 * 12 = 12 miles.

54 + 12 = 66 miles.

66 miles.

D=s *t
d= 3*18=54
d= s * t
d= 1*12=12
54+12=66 
You sure this isn't a math question?

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -