The Ferris wheel will be open for 7:00 - 1:00 = 6 hours.
In one hour the wheel can ride 60 minutes / 20 minutes = <<60/20=3>>3 times the number of riders.
The total per hour riders is 3 * 70 people = <<3*70=210>>210 people.
If the ride is open 6 hours * 210 people = <<6*210=1260>>1260 people can ride.
#### 1260