Parallel equivalent:

1/Rp = 1/R1 + 1/R2 = 1/20 + 1/40 + 1/80 = (4 + 2 + 1)/80 = 7/80

Rp = 80/7 W

Rp in series with 100 W

Req= 80/7 + 100 = 780/7 = 111W

Answer is E

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