1.)By dividing the given costs per pound (6÷9, or 12÷18) you will get the answer of 1.5. This means it is $1.50 per pound.
2.)If you buy 9 pounds of tomatoes at a $1.50 a pound, you have to multiply to find out how much you get. 9×1.5=13.5
They paid $13.50
3.) To find how many pounds you can buy for $19.50, you have to divide 19.5÷1.5 and you will get 13 pounds.