Randi needs to mow her lawn the mixture requires 5 gallons of gas for every 2 gallons of oil how much oil will she need for 8 gallons of gas? In tenths

For every 5 gallons of gas, Randi needs 2 gallons of oil.

Therefore, for 8 gallons of gas, she will need (2/5) * 8 = <<(2/5)*8=3.2>>3.2 gallons of oil.