What is the least common multiple of 3,16, and 20?

Yahir designs bracelets. he uses between 9 and 15 red and yellow beads in the ratio of 2 red bead to 5 yellow beads. drag the beads into the container to meet these requirements

If 3 3/4 lb. of candy costs 20.25 how much would 1lb. of candy cost

Why is it so easy to buy on impulse and overspend with a credit card? what could you do to counteract this tendency?