We can use Newtons second law of motion here.
Mass of student `= 615/9.81 = 62.7`
Weight of student act downward and the reaction of his weight act upward on the scale.
`uarr F = ma`
`645-615 = 62.7*a`
` a = 0.478m/s^2`
Since the acceleration is a positive value the elevator goes upward.
It is true.