Question
A is twice efficient as B and B can do a piece of work
in 40 days. B started the work and after a few days A joined him. They completed the work in 32 days. From the starting, for how many days they worked together?Solution
B’s one day work = `1/40` A’s one day work = `1/20` (A + B) one day work = `1/40+1/20=(1+2)/40=3/40` Now, let us assume A joined B after (32 - x ) days then, `(32-x)/40+(x xx3)/40=1`  `=>(32-x+3x)/40=1`  32 + 2x  = 40  x = 4
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