A work can be completed by 12 boys in 24 days and 12 girls in 12 days. In how many days would the 6 boys and 6 girls working together complete the work?
Choices
A) 12
B) 18
C) 16
D) 20
E) 24

Rationale: in 1 day , 12 boys does 1 / 24 of the total work . = > in 1 day , 1 boy does 1 / ( 24 * 12 ) of the total work = > in 1 days , 6 boys do 6 / ( 24 * 12 ) = 1 / 48 of the total work in 1 day , 12 girls do 1 / 12 of the total work . = > in 1 day , 1 girl does 1 / ( 12 * 12 ) of the total work = > in 1 day , 6 girls do 6 / ( 12 * 12 ) = 1 / 24 of the total work in 1 day , 6 boys and 6 girls do 1 / 48 + 1 / 24 of the total work = > in 1 days , 6 boys and 6 girls do 3 / 48 = 1 / 16 of the total work so , 6 boys and 6 girls complete all work in 16 days . hence , the answer is c
Answer: C