Answer and explanation:
Since a quarter(1/4) of paint covers 80 square feet, a whole paint would cover 80×4= 320 square feet of the wall
Remaining part of the wall left unpainted after using one whole paint
480-320= 160 square feet
Therefore paint required for remaining unpainted part
= 160/80= 2 quarters of paint(1/4+1/4)= 1/2 paint
Total paint required for the wall = one whole paint + half paint = 1+1/2= 1 1/2
Total paint required is one and half
Or
We divide area of wall by area of wall covered by each quarter
480/80=6 quarters of paint
6 quarters of paint = 1/4+1/4+1/4+1/4+1/4+1/4
We still get same answer
= 1 1/2
