Eric, Jose, Shannon, and Jackie wanted to plant a garden . Jose's dad said they could use a rectangular space in the backyard that was 8m by 4 m . The friends decided they would first like to make a colorful border for the garden using small flowering plants called marigolds . If they planted the marigold plants 10cm apart, how many would they need to complete the border ? Draw a model and show a calculation to show your thinking.