Question

The numbers x, y, z are respectively proportional to 2, 3, 5 and the sum of x, y and z is 80. If the number z is given by the equation z = ax-8, then a is

Answer 1

80 = k( 2 + 3 + 5 ) =>  k = 8
Hence,  the numbers are   2k, 3k, 5k  =( 16, 24, 40 )
z = ax -8 => 40 = a * 16 -8 => a =3