Merve plans a 30-day walking program. On the first day, she walks for a certain duration, and plans to walk 1 minute longer each subsequent day than the previous day. Following this plan for the first 15 days, Merve began to struggle and reduced her walking time by 1 minute each day for the remaining days compared to the previous day.
After 30 days, Merve calculated her total walking time to be 1395 minutes.
Accordingly, how many minutes did Merve's first day walk last?
A) 30
B) 35
C) 40
D) 45
E) 50
Merve plans a 30-day walking program. On the first day, she walks for a certain duration, and plans to walk 1 minute longer each subsequent day than the previous day. Following this plan for the first 15 days, Merve began to struggle and reduced her walking time by 1 minute each day for the remaining days compared to the previous day.

After 30 days, Merve calculated her total walking time to be 1395 minutes.

Accordingly, how many minutes did Merve's first day walk last?

A) 30

B) 35

C) 40

D) 45

E) 50