What is a conjunction and disjunction

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Abook store is having a 30 perscent off sale. diary of the wimpy kid books are now 6.30 dollars each what was the original price of the books

The john nash mall used 17,4000 kilowatt hours in may, with a peak load of 92 kilowatts. the demand charge is $5.95 per kilowatt, and the energy charge is $0.08 per kilowatt hour. the fuel adjustment charge is $0.017 per kilowatt hour. what is the total electricity cost for may?