Please help me anyone with this question

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.