Pleas help me with these questions

The cash price of a television is $580.the hire-purchase price of the television is $865.the hire-purchase price is an initial deposit of n% of the cash price and 6 equal monthly payments of $120.find the value of n.

Sole with work in 10 years, the average number of hours of tv watched per week by teenagers dropped from 23.9 to 21.4. find the percent of change.

Explain why the factor 1.5 is broke. into two numbers in the model.