Iwanted to see if i was right, can i get a second opinion? if 15 tickets cost $105, how much will 12 tickets cost? a.$60 b.$72 c.$84 d.$120 i chose answer c!

Karen is financing $291,875 to purchase a house. she obtained a 15/5 balloon mortgage at 5.35%. what will her balloon payment be? a. $220,089.34 b. $219,112.46 c. $246,181.39 d. $230,834.98

How to do this , and can some one explain

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?