The united states uses 4 × 109 megawatt hours of electricity in a year. mexico uses 2 × 108 megawatt hours in a year. how many times more megawatt hours does the united states use than mexico in a year?

(c) the diagram shows the first three shapes of a matchsticks arrangement.first shape = 3second shape = 5third shape = 7given m represents the number of matchstick used to arrange the n'th shape.(i) write a formula to represent the relation between m and n. express m as the subjectof the formula.(ii) 19 matchsticks are used to make the p'th shape. find the value of p.