两道SAT2的数学题,求英语数学专家!

题目

两道SAT2的数学题,求英语数学专家!
1.A cell phone provider charges 0.4刀 for the first minute of a call and 0.2刀 for each additional mitute or each additional portion of a minute.The cost of a call,C,is given by the model C=0.4+0.2T where T is the number of minutes over the first minute and T is the least integer greater than or equal to t.What is the cost of a 12.25-minute call?
85.
2.A teacher gives a test to 2 classes.The first class has 18 students and the second has 24 students.If the average for the first class is 84% and x is the overall average grade for all of the students,then which of the following is true.
完全不明白为什么取值范围是36《x《92

答案

第一题大概是一种电话第一分钟0.4元,以后每分钟0.2元不足一分钟按一分钟记,话费的记取方式为C=0.4+0.2T,T为超过一分钟的时间且为不小于t的正整数.求12.25分钟的话费C=0.4+0.2*（13-1）=2.8 觉得给的答案是不是有问题...