What is the average weight of the three new team members who were recently included in the team?
Average of weight of the three new men = ?
Question is basically asking what is the sum of weights of three men.
(1) The average weight of the team increases by 20 kg
The team can have any number of members.
For example: There are 10 members with the average weight of 50 kg. After 3 new men are added(assuming that they are not replacing existing members) to the team the average becomes 70 kg.
Thus, difference in total weight of team = 70*13 - 50*10 = 410. Hence average weight of 3 new men = 410/3 kg
If there are 10 members with the average weight of 100 kg. After 3 new men are added(assuming that they are not replacing existing members) to the team the average becomes 120 kg.
Then, difference in total weight of team = 120*13 - 100*10 = 560. Hence average weight of 3 new men = 560/3 kg
INSUFFICIENT.
(2) The three new men substitute the earlier members whose weights were 64 kg, 75 kg and 66 kg.
Sum of replaced members = 64 + 75 + 66 = 205 kg.
If there are 10 members with the average weight of 50 kg. After 3 new men replace existing members of the team, weight of 7 members = 50*10 - 205 = 295 kg.
Then, total weight of 3 new men = Average of new team * 10 - 295 = ?
INSUFFICIENT.
Together 1 and 2
If there are 10 members with the average weight of 100 kg. After 3 new men replace existing members of the team the average becomes 120 kg.
Now, weight of 7 members = 100*10 - 205 = 795 kg.
Then, total weight of 3 new men = 120*10 - 795 = 405 kg.
OR
If there are 10 members with the average weight of 50 kg. After 3 new men replace existing members of the team the average becomes 70 kg.
Now, weight of 7 members = 50*10 - 205 = 295 kg.
Then, total weight of 3 new men = 70*10 - 295 = 405 kg.
SUFFICIENT.
IMO Answer C.
_________________