Question

100 W electric bulb is lighted for three hours daily and four 60 W electric bulbs are lighted for two hours daily calculate the unit of energy consumed in the month of 30 days

Answer 1

$energy \: consumed \: by \: electric \: bulb = \\ e = p \times t \\ given \: power \: = 100w \\ given \: time = 3hours \\ now \: substitute \: the \: values \: in \: e = p \times t \\ therefore \: energy \: consumed \: = 100 \times 3 \\ = 300wh \\ \\ they \: have \: asked \: about \: energy \: consumed \: in \: 30 \: days \: then \\ 300 \times 30 = 9000wh$

Next given that 4 bulbs are connected

then,

$e = p \times t \\ e = 60 \times 2 \\ e = 120wh \\ given \: there \: are \: 4 \: bulbs \\ then \: energy \: consumed \: by \: 4 \: bulb \: is \: 4 \times 120 = 480wh \\ calculating \: energy \: consumed \: in \: 30 \: days = 480 \times 30 \\ = 14400wh \: energy \: is \: consumed \: in \: 30 \: das$

hope it helps you