Gerry is knitting a scarf for a friend. She knits a gauge swatch which measures 4 in. by 4 in. If the square is 30 stitches wide and 39 rows long, how many stitches wide will she need to knit in order to make a scarf that is 18 inches wide and 36 inches long?

Gerry will need to knit 135 stitches wide and 351 rows long for make a scarf that is 18 inches wide and 36 inches long.

Step-by-step explanation:

1. Let's review the data given to us for solving the question:

Measures of the gauge swatch = 4 inches * 4 inches

Number of stitches wide of the gauge swatch = 30

Number of rows long of the gauge swatch = 39

2. How many stitches wide will she need to knit in order to make a scarf that is 18 inches wide and 36 inches long?

Using Rule of Three Simple we can found that value, this way;

Number of stitches wide for 18 inches wide = (18 * 30) / 4

Number of stitches wide for 18 inches wide = 540/4 = 135

Gerry will need to knit 135 stitches wide for make a scarf that is 18 inches wide.

We can found the same way, the rows long:

Number of rows long for 36 inches long = (36 * 39) / 4

Number of rows long for 36 inches long = 1,404/4 = 351

Gerry will need to knit 351 rows long for make a scarf that is 36 inches long.