Parallel means lines that never meet, and perpendicular are lines that meet at right angles.
You need to divide the total amount by $75, to see how many DVD players she could buy with the $568.
568÷75= 7 remaining 43
This means that Julia can buy 7 DVD players, and will have $43 extra dollars left over.
Ratio: 15:30 = 1:2
Fraction: 1/2
Percent: 50%
Decimal: 0.5
Time for first plane = 625 / 250
= 2.5 hours
after 1.25 hours
boeing 747 takes 1.25 hours (2.5 - 1.25) to arrive at the same location at the same time
so, speed = distance / time
= 625 / 1.25
= 500
the average speed of the boeing 747 is 500 mph