兩道SAT2的數(shù)學(xué)題,求英語(yǔ)數(shù)學(xué)專家!
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.
完全不明白為什么取值范圍是36《x《92