Helphelphelp me please

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

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

Which of the following statements must be true about this diagram? check all that apply. x°, y°, z°, & w°