Question 838825
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Hi,
kate worked 10 hrs fewer than dave {{{highlight_green(x)}}} hrs
 sarah worked 20 hrs more than dave {{{highlight_green(x)}}} hrs
Question states***3 siblings committed themselves to volunteer 130 
 (x-10hrs) + (x+20hrs) + xhrs = 130hr
    3x = 120hrs
     x = 40hrs, the number of hours Dave worked.
Kate worked 30hrs and Sarah worked 60hrs
CHECKING our answer***
 40hrs + 30hrs + 60hrs = 130hrs
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