When Jack cycles from home to the store, it takes 2 * 50 = <<2*50=100>>100 miles.
He then cycles 50 miles to Peter.
When Peter and Jack cycle back to the store, they cover a total of 50 + 50 = <<50+50=100>>100 miles.
The total number of miles covered is 100+50+100 = <<100+50+100=250>>250 miles
#### 250