Question 627939
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Hi,
If a work is done in 4 days by A and the same work is done in 12 days by B, 
then how many days{{{highlight(x)}}} will it take to complete the work working A and B together?
Question states*** fraction of work done PER day Key
 {{{1/4 + 1/12 = 1/x}}}  |Multiplying thru by 12x so as all denominators = 1
    3x + x = 12     | Solve for x, days it takes to complete the work together