Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
In mid-May, the depth of a river in Moreland is measured. By mid-June, the river is 10 feet deeper than mid-May. By mid-July, the river is three times deeper than mid-June. If the river is 45 feet deep in mid-July, how many feet deep was the river in mid-May?

### Response:
 ในกลางเดือนมิถุนายน แม่น้ำลึก 45/3=<<45/3=15>>15 ฟุต
ในกลางเดือนพฤษภาคม แม่น้ำลึก 15-10=<<15-10=5>>5 ฟุต