Answer:
90 Houses were sold
Step-by-step explanation:
1) First, lets find 1/7 of 210:
210/7
=30
2) Now, lets multiply 30 by 4, because that will be 4/7 of 210:
30*4
=120
3) Now, lets subtract 120 from 210, and find how many houses were sold:
210-120
=90
