John's Bar 60 km away from Ben's Bar.
Doug's Bar is 40 km away from Kieran's Bar
John's Bar is 10 km nearer to Doug's Bar than Kieran's Bar
If I am to assume that these bar are in a liner position,
Ben's Bar Kieran's Bar John's Bar Doug's Bar
************* 60km*******************
*****************40 km ********************
*********30 km**************
Doug's Bar is 90 km away from Ben's Bar.
Ben to John = 60 km
John to Doug = 30 km
Ben to Doug = 60 + 30 = 90 km.