How I slove this qustion

(L.O.4) 3-34. Multiproduct CVP Analysis Rio Coffee Shoppe sells two coffee drinks, a regular coffee and a latte. The two drinks have the following prices and cost characteristics: Latte Sales price (per cup) Variable costs (per cup). Regular Coffee $1.50 .70 $2.50 1.30 The monthly fixed costs at Rio are $6,720. Based on experience, the manager at Rio knows that the store sells 60 percent regular coffee and 40 percent lattes. Required - How many cups of regular coffee and lattes must Rio sell every month to break even