If the vectors point towards the same direction, the magnitude of the vector quantities are added as in, C = A + B. If they point towards opposite direction, the magnitudes are subtracted giving a resultant vector equal to C = A - B.
Distributive property is
a(b+c)=ab+ac
we can make it easier by splitting up 63 into 60+3
so
7(63)=7(60+3)=7*60+7*3=420+21=441
(37.5)(12.5)=x(15)
468.75=15x
x=31.25
she will have to work 31.25 hours in order to earn the same amount of money