If zig really did go to bed at 10 p. m., what is the wattage of the new light bulb?

Alright so here's the catch. Zig knows he went to bed at 10pm , but his calculations show 12pm. So basically,that could mean that his lights went off at 12pm , bc he makes his calculations according to the light bulb (lol , thats why its mentioned in the question). So theres a two hour difference.

Watt is the unit of power , so theyre asking us to find the power of the new bulb.  

power= work done by time.

time= 2hrs

Power=75watts.

we need work done , so work done = power * time = 75*2=150 joules.

but , new bulb works two hours more than previous one , so time taken = 4 hours , work done=150 joules.

therefore power= work done/time= 150/4=37.2 watts.

well if he bought them at 5 cedis each sold them at 7 cedis each then he would make a profit of 2 cedis of each book. if in total he made 150 cedis profit that means he sold 75 books. he lost 12 books at the start so that means he originally bought a total of 82 books.

step-by-step explanation: