A dance troupe has a total of 50 dancers split into 2 groups.

A dance troupe has a total of 50 dancers split into 2 groups. The costumes worn by Group A cost $80 each, and those worn by Group B cost $90 each. If the total cost of all the costumes is $4,270, what is the total cost of the costumes worn by Group B ?

Let A be the number of costumes worn by Group A
Let B be the number of costumes worn by Group B

Using the first statement that a dance troupe has a total of 50 dancers split into 2 groups:
A + B = 50 (Eq1)
Therfore, A = 50 - B (Eq2)

Using the second statements, the costumes worn by Group A cost $80 each, and those worn by Group B cost $90 each. If the total cost of all the costumes is $4,270:
80A + 90B = 4270 (Eq3)

Substituting the value of A in Eq2 into Eq3 we get
80(50-B) + 90B = 4270
4000 - 80B + 90B = 4270
10B = 270
Therefore,
B = 27

We need total cost of the costumes worn by Group B, that is 90B, which is:
27*90= 2430

$90 * 27 = $2430

Answer: C