Ras Bihari, a plumber, earned on an average ₹925 per day in the month of January. He earned on an average ₹881 per day during the first 20 days and ₹915 per day during the last 20 days. What was his average income (in ₹) per day from 12^th January to 20^th January?

805

Total earning in the month Jan. = 31 x 925

Earning in first 20 Days ( 1st jan to 20 Jan) = 20 x 881 --------(A)

Earning in last 20 Days (12th Jan to 31st Jan)= 20 x 915 -------- (B)

(A) + (B) = 20 x (881 + 915)

As above, his total earning from 12th Jan to 31st Jan = 20 x (881 + 915) - 31 x 925 = 7245

Avg. of Ras Bihari's earning from 12th Jan to 31st Jan =  805