Answer:
   (b)  24
Step-by-step explanation:
The given variable definitions and the given relationships let us write these statements:
   LH males = 4 × LH females = 4x
   RH females = 3 × RH males = 3y
   LH males + RH males = 204 = 4x +y
   RH females + LH females = 348 = 3y +x
Your favorite method of solving equations of this sort can tell you ...
   (x, y) = (24, 108)
There are 24 left-handed females.
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<em>Additional comment</em>
Other numbers involved here are ...
   y = 108 . . . . right-handed males
   204-108 = 96 . . . . left-handed males (=4×24)
   348-24 = 324 . . . . right-handed females (=3×108)
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If you want to solve the equations by hand, you can use substitution for y to get an equation in x:
   3(204 -4x) +x = 348   ⇒   -11x = -264   ⇒   x = 24