You first have to find the rate of the DVDs. To do this you need to divide $28 by the number of DVDs, 8. 28/8 equals 3.5 so that means that a single DVD costs $3.50. To find the rate of 5 DVDs you need to multiply the rate of a single DVD by 5: 3.50 x 5= 17.50 5 DVDs costs $17.50 and the unit rate is $3.50 per DVD
