This is a conversion problem. You are given one meter of yellow ribbon and 28 centimeters of blue ribbon. You are required to find for the number of centimeters of ribbon she needs. Note that there are 100 centimeters in one meter. So you have to convert the one meter of yellow ribbon into 100 centimeters of yellow ribbon. Then add the ribbons, 100 plus 28 equals 128 centimeters of ribbon. So Audrey needs 128 centimeters of ribbon all in all.