Answer:
30%
Step-by-step explanation:
The two outcomes (can work the problem and can't work the problem) are complementary.
In probability theory, the complement of any event A is the event [not A], i.e. the event that A does not occur. The event A and its complement [not A] are mutually exclusive and exhaustive.
Complementary events are two outcomes of an event that are the only two possible outcomes.
Complementary outcomes add to 1 or 100%.
100 - 70 = 30.
