word problem
posted by jen .
Working together, Larry, Moe and Curly can paint an elephant in 3 minutes. Working alone, it would take Larry 10 minutes or Moe 6 minutes to paint the elephant. How long would it take Curly to paint the elephant if he worked alone?
Thanks.

Larry paints L elephants/minute
Moe paints M elephants per minute
Curley paints C elephants per minute
(L + M + C )(3) = 1 elephant
(L) (10) = 1 elephant
(M)(6) = 1 elephant
so
L = 1/10
M = 1/6
(1/10 + 1/6 + C )(3) = 1
3/30 + 5/30 + C = 10/30
C = 2/30 = 1/15 elephants per minute
so
15 minutes per elephant