Working alone

Tom and Chandri are doing household chores. Chandri can do the work twice as fast as Tom. If they work together, they can finish the work in 5 hours. How long does it take Tom working alone to do the same work?

Result

T =  15 h

Solution:

C=T/2  5(1/C+1/T)=1 5(2/T+1/T)=1 5 3/T=1 T=5 3=15 h=15  h   C=T/2=15/2=152=7.5 h  x=5 (1/C+1/T)=5 (1/7.5+1/15)=1 x=1C = T/2 \ \\ \ \\ 5(1/C + 1/T) = 1 \ \\ 5(2/T + 1/T) = 1 \ \\ 5 \cdot \ 3/T = 1 \ \\ T = 5 \cdot \ 3 = 15 \ h= 15 \ \text { h } \ \\ \ \\ C = T/2 = 15/2 = \dfrac{ 15 }{ 2 } = 7.5 \ h \ \\ \ \\ x = 5 \cdot \ (1/C + 1/T) = 5 \cdot \ (1/7.5 + 1/15) = 1 \ \\ x = 1







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