The equation below describes a proportional relationship between x and y. What is the constant of​ proportionality?

Molly shared a spool of ribbon with 12 people. each person received 3 feet of ribbon. which equation can she use to find r, the number of feet of ribbon that her spool originally had?

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

Astock has a 25% probability of increasing by $10 and a 75% probability of decreasing by $5. what is the stocks expected increase or decrease?