Problem: a rectangular courtyard , the sides of which are in the ratio of 4 : 3 , cost rs . 600 for paving at 50 p per m 2 ; find the length of the diagonal of the courtyard ? 
Options: ['a ) 17 m', 'b ) 45 m', 'c ) 54 m', 'd ) 77 m', 'e ) 34 m']
b