Solution:
Alex borrowed ₹ 1,25,000 from the bank.
He paid ₹ 12,500 every month for a year.
The extra money he paid was the interest amount.
1 year = 12 months
Amount he paid back to the bank at the end of a year = ₹ 12,500
12= ₹ 1,50,000
Interest = Money repaid - Money Borrowed
= ₹ 1,50,000 - ₹ 1,25,000
= ₹ 25,000