Answer: 30 students more voted for Gerardo than for Juju.
Explanation:
so 'x' represent the total number of students
0.40x of the students voted for Gerardo
0.35x of the students voted for Leandro
0.25x of the students voted for Juju
70 students voted for Leandro:
0.35x = 70
by solving we find:
x = 200 students
0.40x - 0.25x = (0.40 - 0.25)x = 0.15x = 0.15*200 = 30