Answer:
71x+50y
Step-by-step explanation:
D both are right triangles
Time taken by Ria to paint a room = 4 hours
Time taken by Destiny to paint a room = 6 hours
If they work together, they complete 1 job. So,

The LCD of 4 and 6 is 12




Hence, both of them can paint the room in
hours or 2.4 hours.
9+-3 means 9 plus 3 less
basically it is 9-3=6