for question 4, it is best to draw a model. the difference between the skirt and shoe is 2 units which equals to $30. you need to find out the total cost as part of calculating your average. average = total cost/total no. of items which in this case is $120/2 = $60

for question 5, it is best to change them to the same rate which means convert machine Q's rate per 2 minutes into 1 min. you need to find out how much both machines print in 1 min. then divide total no (4560)/no. of cards per min (120) = 38 mins

let me know if you need further explanation! :)