Concept: The question tests on the basics of Median and Mean.
Though we totally agree that the phrasing of the statement is rather unclear of its inherent meaning, we can still conclude that this statement DOES NOT give us any information about the pricing of remaining 19 houses. Thus, we cannot say whether 9 of the 20 houses are priced less than $160,000 or not.
In a set of 20 numbers, the median
= 10th term + 11th term/2
Thus, Median= $150,000 in the following cases:
(a) Case 1
When the values of both, 10th and 11th term is $150,000.
(b) Case 2
When 10th term is as less from $150,000 as 11th term is greater than $150,000.
=>150000-10th term = 150,000+11th term
However, in both the cases at least 10 terms will be less than $150,000. Hence (option B)