2a) Basically Samuel works for 6 hours a day and earns 7.50 per hour, so you have to do 7.50 x 6 to see how much he earns per day (which in this case is $45). You then have to multiply $45 to 4 since he earns $45 per day and works 4 days per week (which is $180).
2b) After finding out how much he earns per week ($180 from the previous question), you then have to multiply $180 by 8 as $180 is the amount he earns per week and since he works for 8 weeks you have to multiply $180 by 8 (the answer is then $1440).
sorry if I'm not making sense, i tried :) good luck!