math!
posted by Lewis
You have 48 minutes to take an exam of 21 questions. After you finish the first 10 questions, you realize you must answer the remaining questions twice as fast to finish the exam.
How many questions per minute were you answering?
Also, how many questions per minute must you now answer to finish the exam on time?

Damon
q = first questions/min
2 q = final que/min
t min for first ten
48  t min for final 11
q t = 10 so t = 10/q
q t + 2q(48t) = 21
10 + 96q  20 = 21
96 q = 31
q = 31/96 questions/min
so twice that = 62/96 to finish
========================
check
t = 960/31 = 30.97 min
48t = 17.03 min
30.97 * 31/96 = 10
17.03 * 62/96 = 11
sum = 21 sure enough
Respond to this Question
Similar Questions

ap english exam
Does anyone know where I can find a free online copy of questions 2843 on the 1996 AP English Language & Composition Exam? 
Probability (PreCalculus)
A class is given a list of eight study problems from which five will be part of an upcoming exam. If a given student knows how to solve six of these problems, find the probability that the student will be able to answer: (a) all five … 
Math
You can answer any 8 questions from the 12 questions on an exam. In how many different ways can you choose the 8 questions, assuming that the order in which you choose the questions is irrelevant? 
Math(Factorial)
A women student is to answer 10 out of 13 questions on a test. Find the number of choices where she must answer: (a) the first two questions; (b) the first or second questions but not both; (c) exactly 3 out of the first 5 questions … 
statistics
You can answer any questions from the questions on an exam. In how many different ways can you choose the questions, assuming that the order in which you choose the questions is irrelevant? 
Math
An exam consists of six trueorfalse questions. Assuming that every question is answered, in how many different ways can a student complete the exam? 
Math
I do not understand this problem, and I must write an inequality for it too: Nilsa is working on a 60 minute math test. There are 20 questions on the test. If it takes her 20 minutes to complete 12 of the questions, what is the greatest … 
Algebra 2
You have 48 minutes to take an exam of 21 questions. After you finish the first 10 questions, you realize you must answer the remaining questions twice as fast to finish the exam. How many questions per minute were you answering? 
Statistics
A student s to answer 10 out of 13 questions in an exam. How many choices he has if he must answer at least 3 of the first 5 questions. 
Math
The trigonometry practice exam has 6 questions with the answer A 8 questions with the answer Baby 10 questions with the answer C and 9 questions with the answer D The number of different answer keys that can be created with the letters …