Tahir gets paid travelling expense's according to the distance he drives in his car plus a weekly sum of Tk. 21. He claims for 420 miles travelled and receives an expenses payment of Tk. 105 . What is the payment rate per mile?

প্রশ্নঃ Tahir gets paid travelling expense's according to the distance he drives in his car plus a weekly sum of Tk. 21. He claims for 420 miles travelled and receives an expenses payment of Tk. 105 . What is the payment rate per mile?