What variable is used to represent slope?

In the rectangle below ac=30 units what is de

Stacey filled her 1/2 cup of measuring cup seven times to have enough flour for a cake recipe how much flour does the cake recipe calls for

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?