Let b be the number of trips Bill makes and j be the number Jean makes. We know that b + j = 40, and j = b + 6.
Substituting the first equation into the second equation, we get b + b + 6 = 40
Combining like terms, we get 2b + 6 = 40
Subtracting 6 from both sides, we get 2b = 34
Dividing both sides by 2, we get b = 17
Substituting that value back into j = b + 6, we get j = 17 + 6 = <<17+6=23>>23
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