Answer:
The distance cover by Bell is 8 miles .
Step-by-step explanation:
Given as :
The distance cover by Mike = The distance cover by Pete = D miles
Let The distance cover by Bell = d miles
The distance cover by Mike = 15 miles + distance cover by Bell
i.e D = 15 + d ............1
Again
The distance cover by Pete = three time distance cover by Bell - 1 miles
i.e D = 3 × B - 1
Or, D = 3 d - 1 ............2
Now, Solving equation 1 and 2
So, 15 + d = 3 d - 1
Or, 3 d - d = 15 + 1
Or, 2 d = 16
∴ d = 
i.e d = 8 miles
So,The distance cover by Bell = d = 8 miles
Hence, The distance cover by Bell is 8 miles . Answer