Question. In Mary's class, there are 25 students. Their teacher told them they could pay $50 each to finance a big science project that they and their society would benefit greatly from. They all paid the full amount except for 4 students, who paid half. How much was the class able to gather together?
Answer. 1150
What step-by-step reasoning justifies that answer?
Reasoning: The original amount is $50 so half is $50 / 2 = $25. 4 students paid half ($25) for a total of 4 * $25 = $100. There are 25 - 4 = 21 students left. 21 students paid the full amount ($50) for a total of 21 * $50 = $1050. They were able to gather a total of $100 + $1050 = $1150.