Write it as a mixed fraction 7/5 = 1 2/5
Subtract 4x from both sides
Then divide both sides by 9 to isolate y
Y=(6-4x)/9
It took them 4 days to install 480 chairs which means if they were working at a constant rate they got 120 chairs installed daily. with 360 chairs left that means in 3 days they will finish. so overall, it took the workers 7 days to finish, or a week.
A number in the tens place 84