Question

David made 30 cups of tea per hour. Andrew made 35 cups of coffee per hour. This week David made an additional 10 cups of tea. Write an expression that represents the weekly cups of tea and coffee. D = the number of hours that David made tea this week. A = the number of hours Andrew worked this week?

Answer 1

X = cups of tea per hour
y = cups of coffee per hour

David makes 30 cups of tea per hour = 30x
David works for D hours this week.

Therefore number of weekly cups of tea = number of hours * cups of tea per hour
This is 30x * D = 30Dx

For Andrew, it is similar
30Ay
Because Andrew made an additional 10 cups, then it is 30Ay + 10
(cups of coffee this week)