I don't see where you get that you'd only do incs over 5 rows.... or did you mean 5"?
First inc at the end of the next row, and every other row for 10 rows total  that's 10 sts so you'd now have 44 sts. Then inc on every 4th row twice  that's 2 more sts, for 46. You're also to inc at the beg of the 5th row and every 6th row twice which adds another 3 sts to get you to 49. This all takes place over 28 rows, not 42, plus the first 2 rows which would be 30 altogether.
And that does seem to be 5" worth. Do you have a link to the pattern?
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sue knitting heretic
