In order to calculate rate or average speed you divide miles by time
I got 153.8 by dividing 500 by 3.25 (the .25 is because 15 minutes is 1/4 of 60) hope this helped!!
Since she has painted 60% of her bedroom so far, 40% must remain. In order to know how many square feet that is, we take the total amount of square feet she needs to paint and multiply it by 0.4
45*0.4 = 18 square feet
Well perimeter is lengthx2 and widthx2 so 7x2=14
then 64-14=50
50÷2= 25
length=25