This is kind of a personal question that I need an Answer and explanation:

So I went to the mall with my cousins. My mom said to buy my little sister something from the mall that was $15 budget. She would reimburse me for the $15 dallors spent. When we got to the mall I spent $24 on her stuff. My mom said she owned me $10. Her math was 24 - 15 = 9. but why not just give me my $24 for spending on her?

You drop a rubber ball off the roof of a 50 meter high building onto a paved parking lot. it bounces back up with every bounce, but not quite all the way back up to you. after the first bounce it bounces back only 80 percent of the distance it was dropped from. the pattern continues, meaning after every bounce it comes up to just 80 percent of the previous maximum height. so if before the first bounce the height is 50 meters, what height does the ball reach after the fifth bounce? round your answer to one decimal place and chose the correct response from the choices below:

Find an equation for the linear function which has slope -10 and x-intercept -7

Which one ? is the answer and how to find this answer