Answer: 0.28
Step-by-step explanation:
Let´s name the proportion of orders
The sum of all of these proportions is equal to the total quantity of orders.
Therefore,
N + O + M = 1
Then, substracting N and O on each side of that equation,
the proportion of orders with more than one optional feature (M) is:
M = 1 - N - O
M = 1 - 0.38 - 0,34
M = 0.28