Supriya has a pre-paid electricity connection at home. On a sultry Sunday afternoon, she checks that she only has ₹9 left in the balance. She wants to use the air conditioner (AC), rated at 1.2 kW. The price of electricity is ₹10 /unit in her area. How long can she run the AC before her balance is over and the power runs out?

0.75 hour(s) or 45 minutes

Explanation:

1 unit of electricity = 1kwh

Amount of energy consumed by 1kw load in one hour

Price per unit = ₹10

Air conditioner rating(power) = 1.2Kw

Given that balance = ₹9

Therefore, supriya's total energy cost = energy balance = ₹9

Total energy cost = power in kilowatt × time of operation (in hour) × cost per unit

₹9 = 1.2kw × time × ₹10

₹9 = 12 × time

Time = 9 / 12

Time = 0.75 hours

0.75 × 60 = 45 minutes

i believe the answer would be:

d. violin, clarinet, french horn, and tuba