It takes Alexis 2 x 6 = <<2*6=12>>12 hours to sew 6 skirts
It takes Alexis another 7 x 4 = <<7*4=28>>28 hours to sew 4 coats.
In total it takes Alexis 12 + 28 = <<12+28=40>>40 hours to sew 6 skirts and 4 coats.
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