Purchase Solution

Number Patterns : Door Problem

Not what you're looking for?

Ask Custom Question

A school had a very unusual tradition involving its 1000 students and its 1000 lockers. On opening day, after the head of the school had closed all the lockers, a student walked by and opened every single one. A second student then closed every second one (#2, 4, 6, 8 etc). A third student then changed every third locker (#3,6,9,12 etc), that is, she opened the ones that were closed and closed the ones that were open. A fourth student then changed every fourth locker, after which a fifth student changed every fifth locker , and so on until all 1000 students had passed by all 1000 lockers. At the end of this strange activity, which lockers were open?

Purchase this Solution
Solution Summary

A door problem is solved. The expert examines number patterns.

Solution Preview

A school had a very unusual tradition involving its 1000 students and its 1000 lockers. On opening day, after the head of the school had closed all the lockers, a student walked by and opened every single one. A second student then closed every second one (#2, 4, 6, 8 etc). A third student then changed every third locker (#3,6,9,12 etc), that is, she opened the ones that were closed and closed the ones that were open. A fourth student then changed every fourth locker, after which a fifth ...

Purchase this Solution
Free BrainMass Quizzes
Know Your Linear Equations

Each question is a choice-summary multiple choice question that will present you with a linear equation and then make 4 statements about that equation. You must determine which of the 4 statements are true (if any) in regards to the equation.

Multiplying Complex Numbers

This is a short quiz to check your understanding of multiplication of complex numbers in rectangular form.

Solving quadratic inequalities

This quiz test you on how well you are familiar with solving quadratic inequalities.

Exponential Expressions

In this quiz, you will have a chance to practice basic terminology of exponential expressions and how to evaluate them.

Graphs and Functions

This quiz helps you easily identify a function and test your understanding of ranges, domains , function inverses and transformations.

View More Free Quizzes
Related BrainMass Solutions

  • volume of the box

    How many cubic inches of wood will be needed for the door? Give solution exactly as a mixed number. Include correct units with your answer. 3. Solve the problem. Tim has $582 saved.

  • Serial Problem

    We can interpret the problem into this form: A serial of numbers: 1, 2, 3, 4, 5 ... n (all numbers are positive, which stands for closing door.) Each time a guest multiplies the serials by -1 that is a multiplier of its own number.

  • Keys, Marbles and Class

    Number of ways to select 1 out of 3 non-front door keys to lose = 3C1 = 3 Total number of ways to select 1 out of 5 keys = 5C1 = 5 Probability you can get into your house through the front door = 3/5 2) a) Use the formula for conditional probability

  • Probability: Number of possible access codes

    Probability of not selecting correct access code = 1 - 1/512 = 511/512 This solution helps with a problem regarding number of possible access codes.

  • Case: Let's Make a Deal.

    It discusses the Monty Hall problem in detail with different configurations. A reference link is provided.

  • product of powers of primes

    If a door number has an even number of divisors, it will be closed. If a door number has an odd number of divisors, it will be open. Only perfect squares have an odd number of divisors. The product of powers of primes is applied.

  • KAK Market Data

    A client's contract calls for door-to-door personal interviews.

  • Teacher Using Reflection to Solve Problems in the Classroom

    If the student refuses to sigh the form or give a phone number, it will result in Step 8 If, after signing the form describing all of the steps the student has been through or if the student refuses to sign the form or give a phone number, and

  • force applied to outer edge at right angles to the door

    Here's the problem: A massive shield door at a neutron test facility at Lawrence Livermore Laboratory is the world's heaviest hinged door.

View More Related Solutions