Online Course Discussion Forum

Week 1 Homework Problem #9

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Week 1 Homework Problem #9
by Duy Duong - Saturday, December 5, 2020, 11:34 AM
Does anyone have any ideas on how to solve this problem?  I'm stuck. 
Picture of Charles Zhang
Re: Week 1 Homework Problem #9
by Charles Zhang - Saturday, December 5, 2020, 1:22 PM

I actually got #9 correct (after thinking about it for hours and writing it on my whiteboard multiple times, and maybe writing a python program to do it for me)

My method was setting X and Y to be the base-5 and base-6 counterparts of N, respectively, and setting

N = abc (base 10)

X = defgh (base 5)

Y = jkmn (base 6)

Where the letters denote digits. (i.e. abc could be 243 or 398)

Then from here, remember that

X = 625d + 125e + 25f + 5g + h in decimal

Try converting all of them to decimal.  Remember N=X=Y in decimal!

Try getting an equation that relates c, h, and n, and then use the fact that the last 2 digits of S = the last 2 digits of N.

There are probably better solutions.

This is Charles Zhang, signing off for now.