print "----welcome----"


capacity = input ("please enter the capacity of the fuel tank in gallons, gallons must be between 6 & 20:")
while capacity < 6 or capacity > 20:
 capacity = input ("sorry invalid number,please enter gallons  between 6 & 20:")




efficiency = input ("please enter the fuel efficiency in MPG, efficiency must be between 20 & 75:")
while efficiency < 20 or efficiency > 75:
    efficiency = input("sorry invalid number,please enter MPG  between 20 & 75:")



pricepergallon=input ("price per gallon of petrol? £, price must be between £3.20&4.20:")
while pricepergallon < 3.20 or pricepergallon > 4.20:
 pricepergallon= input ("sorry invallid price,please enter price between £3.20 & £4.20:")


carcango= capacity * efficiency

print " on a full tank, the car can travel" ,carcango, "miles"

print "the cost of travelling 100 miles is £", (100.0/efficiency *pricepergallon)

print "end of program"