week 1 they sell X
week 2 they sell X+5
week three they sell 2(X + 5)
X + X + 5 + 2(X + 5) = 431
X + X + 5 + 2X + 10 = 431
4X + 15 = 431
4X = 416
X = 104
so
week 1 = 104
week 2 = 104 + 5 = 109
week three = (double week 2) = 218
and a quick check
218 + 109 + 104 = 431 --------- OK
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Julie = X
ted = 2X
mike = 3X
X + 2X + 3X = 210
6X = 210
X = 35
so Julie = 35
ted = 70
mike = 105
quick check
35 + 70 + 105 = 210 --------------- OK
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integer 1 = X
integer 2 = X + 1
integer 3 = X + 2
integer 4 = X + 3
X + X + 1 + X + 2 + X + 3 = 114
4X + 6 = 114
4X = 108
X = 27
quick check
27 + 28 + 29 + 30 = 114
