5 dresses and 8 shirts cost $1709.
3 shirts cost $75 less than 1 dress.

For every 3 shirts sold, the price is $75 less than 1 dress. This is counted as one set. For every 15 shirts sold (5 sets), the price is $75 x 5 = $375 less than 5 dresses.

Let’s pretend the person buys 15 new shirts instead of the 5 dresses. He would have paid $375 less, or $1709 - $375 = $1334. This is the amount for a total of 23 shirts (8 shirts + 15 new shirts).

23 shirts = $1334
1 shirt = $1334 / 23 = $58

So 1 shirt costs $58.

method 1
3 s + 75 = 1 d
15 s + 375 = 5 d

5 d + 8 s = 1709
15 s + 375 + 8 s = 1709
1 s = $58



method 2
unit cost
s: 1u
d: 3u + 75

5 x (3u+75) + 8 x 1u = 1709
u = 58

cost of 1 shirt is $58


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Thank you