A clerk spent his 35 hour work week as follows 1/5 of his time in the Sorting mail 1/2 of its time in sorting letters and 1/7 of his time in reception work the rest of his time was devoted to messenger work that percentage of time spent on messenger work by the clerk during the week was most nearly

Answer 1

Not sure how "sorting mail" and "sorting letters" are different, but I'll guess that
1/5 + 1/2 + 1/7 = 59/70
so, 11/70 was spent on messenger work

or maybe 1/2 of the 1/5 was somehow involved. It's all kinda murky.