Answer:
18
Step-by-step explanation:
First we find out how much were sold last month:
1/3 x 45 = 15
Then we know that there are still 30 houses left to sell because 45 - 15 = 30
The houses that were sold this month:
2/5 x 30 = 12
Because we know that 12 more houses were sold, the remaining would be 30 - 12, which is 18