Sunday, March 22, 2009

5-star challenge #3

Grades 11 & 12 5-Star Challenge #3
The number n expressed in base b has the form 364. In base (b+3), n is written as 202. Find the decimal values of n and b, which are both positive integers.

Grades 9 & 10 5-Star Challenge #3
The new tuck-shop coupons are printed only for 7 rupee and 11 rupee denominations. What is the largest integer number of rupees which cannot be paid using a combination of 7- and 11- rupee coupons?


  1. I liked your explanation of this to me- thanks for teaching me math! :) You impress me so much! I love you!

  2. I have scheduled the solution to post itself on March 27. I felt a bit lame answering my own question before anyone had a chance to read it. It's bad enough that I post comments on my own blog, just to feel like somebody cares, even if it's only me, and I don't.

  3. Question 1: b=8, n=244

    Question 2: 59 rupees

    I have to admit that I solved both of these by trial and error, not by some elegant method - so I'll be looking forward to your explanations.