@ bear 1---- A & B can finish a piece of work in 30 days. B and c in 40 days,while c and a in 60 days . how long will they take to finish it together

a- 26 2/3 days(26 whole 2 by 3)
b- 25 days
c- 14 days
d - 16 days

while solving this why u multiplied 2

2(1/A+1/B+1/C) ???????

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