A question of CE Physics

18.

I = P/V

Let n be greatest number of light bulbs without triggering the circuit beaker.

Total current ≤ 15A
(1100/220) + (550/220) + n(100/220) ≤ 15
5 + 2.5 + (5n/11) ≤ 15
5n/11 ≤ 7.5
5n ≤ 82.5
n ≤ 16.5

Hence, the greatest number of light bulbs = 16