What is a common mistake made in budgeting?

over-estimating expenses
budgeting for financial goals or savings last
writing the budget down
all of the above

Can someone me with this problem . show your work .

When the ball has traveled a distance of

Water flows at a steady rate from a tap. its takes 40 seconds to fill a 4 litre watering can from the tap. the rate at which water flows from the tap is halved. complete: 4 litres into cm3