Answer: The required number of houses is 200.
Step-by-step explanation: Given that in a housing estate, the direct proportion of flats to houses is 2 : 5 and there are 80 flats.
We are to find the number of houses.
Let 2x and 5x represents the number of flats and houses respectively.
Then, according to the given information, we have
Therefore, the number of houses is given by
Thus, the required number of houses is 200.