Acistern can be completely drained by a pipe in 6 hours. it can be filled by two pipes in 4 hours and 5 hours, respectively. how many hours will the empty cistern take to fill if all the pipes are running? if x is the time to fill it, which of the following equations could be used to solve for t? 4x + 5x - 6x = 1 15x + 12x - 10x = 60 4x + 5x = 20

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation: