Answer:
number of cans = 10
number of packages orded = x
1 package = 6 cans
total cans = y
total cans = cans sitting on shelf + ordeded packages of cans
y = 10 + 6x ( D )
why 6x ? because we don't know how many packages of cans(x) are ordered but we do know that in 1 package there are 6 cans . so in order to know how many cans are ordered, 6 must times the number if packages ordered that is x. that's why it becomes 6x.