A worker is hired for 7 days. Each day, he is paid 10 Taka more than what he is paid for the previous day of work. The total amount he was paid in the first 4 days of work equaled the total amount he was paid in the last 3 days. What was his starting pay?

Correct Answer: 90
ধরি, লোকটির starting pay x টাকা ∴ x + x + 10 + x + 20 + x + 30 = x + 40 + x + 50 + x + 60 ⇒ 4x + 60 = 3x + 150 ⇒ 4x - 3x = 150 - 60 ∴ x = 90