The density function of the continuous random variable x, the total number of hours, in units of 100 hours, that a family runs a vacuum cleaner over a period of one year is given below: f(x) = { x, 0 < x < 1 8 − x, 1 ≤ x < 2 0, otherwise Find the average number of hours per year that families run their vacuum cleaners?

you never say the total so we cant find the percentage used for petrol

step-by-step explanation:

it will cost dollar $540

the living room is 3 which means if we divide 325/3 then we get $108

therefore if 1part of the living room cost $108 and 3 costed $325

then total 5part of the room will cost 5*108 which gives $540

2.2°  

step-by-step explanation:

let θ = the angle of elevation.

tanθ =77/2020

tanθ = 0.038 12

      θ = tan⁻¹0.038 12

      θ = 2.2°