Answer:
Out of 15 deliveries in one week, 5 are plants
Step-by-step explanation:
At an aquarium, 6 out of 18 deliveries are plants.
Ratio of plant to delivery is given by

Now we need to find out of 15 deliveries in one week, how many are plants.
Total number of plants is given by 15 r.

Out of 15 deliveries in one week, 5 are plants