Okay, no one got the correct answer so here’s how I solved it.
I started by drawing it out which always helps me “see” what I’m trying to solve. With what we know initially, here’s how it looks for a, b, c, d, and e respectively: [bX2] [ ? ] [a+b] [aX4] [(cX2) or (d-b)].
So beginning with the unknown b, I first tried “2”. That made a=4 but made d=16, too large (needs to be a single digit). So I tried making b=1. That made a=2, c=3, d=8 and e=7 which matched all the criteria. So the answer is 21387.
Marilyn has a much longer but more detailed answer on Parade’s site if you want to follow her reasoning. Thanks to all who that tried ( or guessed). I’ll post more of these from time to time.
A number has five different digits, none of which is 0: (a) The first plus the second equal the third digit; (b) the third times 2, plus the second, equals the fifth; (c) the second times 2 equals the first; (d) the first times 4 equals the fourth; and (e) the fourth minus the second equals the fifth. What is the number?
Doug