Hello i have a few questions please can you help.

Kerosene lanterns similar to the Duplex lamp are still widely used in developing countries. An alternative form of lighting for a rural village is to distribute electric lanterns that use LED lamps and batteries which can be recharged weekly from large PV panels.

Q1- A typical LED lamp has a luminous efficacy of 75 lumens per watt of electricity consumed. Calculate how many watts of electricity would be required by a lamp providing equivalent light output to the kerosene lantern with a an output of 70 lumens and Lamp efficacy 0.15 lumens W-1

Q2- A typical modern D Cell rechargeable torch battery can hold 9.4 watthours of electricity. How many such cells would be required to operate such an equivalent lantern used for 4.0 hours a day for a week?

Q3- It is estimated that globally kerosene lamps consume 80 thousand million litres of kerosene fuel per year. If the properties of the Duplex lamp above were to be regarded as typical of them, roughly how many million battery lamps would need to be manufactured to replace them all?