John and Doug each have a paper route. John has 7 times as many newspapers to deliver as Doug. After Doug took some of John's papers, each boy had 40 papers to deliver. How many newspapers did Doug take?
+37170 j = 7d given
let 's' = papers taken from j
j - s = 40 j= 40 + s
d + s = 40 d = 40 -s sub these into the original equation
40+s = 7 (40-s)
s = 30 papers
