Please answer it asap. i'll give positive rating.

Suppose that the battery failure time, measured in hours, has a PDF given by f ( x ) = 2(x+ 1) -3, for x 2 0 EW If there's an appliance functioning with such batteries, on average how many batteries would be required to keep it running for two days? Select one: O 48 O 241 12 O 61 None