请高手解决数学题，谢谢

skyline89

这是问题：

The total costs for a design project was $10,841. The project was carried out by technicians earning $137 per day and draftsmen earning $82 per day. If 98 man days were used on the project, how many man days were draftsmen employed?

谢谢。

迦南門

Total costs $10,841
Total 98 man day

Technicians earning $137 per day
Draftsmen earning $82 per day

Technicians work 51 day x $137 = $6,987
Draftsmen  work 47 day x $82    = $3,854

Total $6,987 + $3,854 = $ 10841

欧河流

X - man days were technician employed
y - man days were drafts men employed

137x+82y=10841,
were x+y=98
x=98-y,
hence, 137(98-y)+82y = 10841
13426-137y+82y = 10841
y = 47 man days