Go Pro!

Christmas Tree Lights

Pro Problems > Math > Number and Quantity > Number Theory > Diophantine Equations

Christmas Tree Lights

I have some strings of red lights, and some strings of green lights for my Christmas tree. All my strings of red lights have the same number of lights on them, and all my strings of green lights have the same number of lights on them.

All the strings of lights have at least 10 lights, and no more than 50 lights.

If I put all of the red-light strings and all the green-light strings on the tree, I would have a total of 278 lights. If I used all of my red-light strings, and only four of my green-light strings, I would have 159 lights.

How many strings of each do I have, and how many lights are on each string?

Presentation mode
Problem by Mr. Twitchell


In order to make it feasible for teachers to use these problems in their classwork, no solutions are publicly visible, so students cannot simply look up the answers. If you would like to view the solutions to these problems, you must have a Virtual Classroom subscription.
Assign this problem
Click here to assign this problem to your students.

Similar Problems

Integers M and N

Find all positive integers M and N such that M2 + MN = 7.

Sum and Difference

The square of the difference of two numbers is subtracted from the square of the sum of two numbers. The result is 144.

If both of the numbers are positive integers, find all possible values for the sum of the two numbers.

The Lobstah Coin

The Maine State Legislature decided to introduce a new coin into our currency, called the lobstah coin. Bertha has the same number of nickels, dimes, and lobstahs in her pocket, totaling $3.19. How many cents is a lobstah worth, if its value is not a fractional number of cents, and Bertha has at least 2 of each coin?


x and y are positive integers such that xy + x = 23, Find all possible ordered pairs (x,y).

Blogs on This Site

Reviews and book lists - books we love!
The site administrator fields questions from visitors.
Like us on Facebook to get updates about new resources
Pro Membership