Answer:
Total earnings = 15d + 0.25r + 2h
(I guess there's a point missing in the second option. Ti should be 0.25r)
Step-by-step explanation:
The student earns:
1. Fixed $15 per day. This means that if he worked "d" days, he would earn $15d
2. $0.25 for each raffle ticket he sells. This means that if he sold r tickets, he would earn $0.25r
3. $2 for each hour he works on the game. This means that if he worked h hours, he would earn $2h
Now, to calculate his total earnings, he would simply add the amount he earned from each of the above criteria.
Therefore:
Total earnings = 15d + 0.25r + 2h
Hope this helps :)