<human>:  A milk teas shop was able to sell a total of 50 cups of milk tea yesterday. Two-fifths of their sales are winter melon flavor, three-tenths are Okinawa flavor, and the rest are chocolate flavor. How many cups of chocolate-flavored milk tea were they able to sell yesterday?
<bot>: How many cups of winter melon-flavored milk tea were sold? ** A milk tea shop sold 50 x 2/5 = <<50*2/5=20>>20 cups of winter melon-flavored milk tea.
How many cups of Okinawa-flavored milk tea were sold? ** They sold 50 x 3/10 = <<50*3/10=15>>15 cups of Okinawa-flavored milk tea.
How many cups of winter melon and Okinawa flavors milk tea were sold? ** So they sold a total of 20 + 15 = <<20+15=35>>35 cups of winter melon and Okinawa flavors milk tea.
How many cups of chocolate-flavored milk tea were they ableel sell yesterday? ** Therefore, they sold 50 - 35 = <<50-35=15>>15 cups of chocolate-flavored milk tea.
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