210 new houses were built. This year 4/7 of them were sold how many houses have been sold?

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