The average monthly wage of a group of 10 persons is ₹ 9000. One member of the group, whose monthly wage is ₹ 8100, leaves the group and is replaced by a new member whose monthly wage is ₹ 7200. Find the new monthly average wage.
Average monthly wage of 10 persons = 9,000Rs
Total wage of 10 person = 10×9000 = 90,000 Rs
The wage of one member of the group = 8100 Rs
When one member leaves the group then total wage of 9 person = 90000 -81900 Rs
The wage of new member = 7200 Rs
When new member join to the group then total wage of 10 person = 81900 + 7200 = 89100Rs
New monthly average = 
Hence new monthly average is 8910 Rs.
6