How many members of Group G are less than 25 years of age?

Target question: How many members of Group G are less than 25 years of age?

Statement 1: Exactly 3/5 of the members of Group G are 25 years of age or older.
Since we have no information regarding the total number of members in group G, there's no way to answer the target question with certainty.
So, statement 1 is NOT SUFFICIENT

Statement 2: The 24 men in Group G constitute 30 percent of the groups membership
This statement provides no information regarding members who are less than 25 years of age.
Statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Let T = the total number of members in group G.
From statement 2, we can write: 24 = 30% of T
In other words: 24 =0.3T
Divide both sides by 0.3 to get: 80 = T
In other words, there are 80 members in Group G

Statement 1 tells us that 3/5 of the members of Group G are 25 years of age or older.
So the number of members who are 25 years or older = 3/5 of 80 = 48
The answer to the target question is there are 48 members who are less than 25 years of age
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Answer: C

Cheers,
Brent