perplexus.info :: Numbers : A Quicky III

A Quicky III (Posted on 2014-04-09)

If each of the a,b,c,d is a decimal digit - for how many ordered quadruplets (a,b,c,d) is the sum S= a+b+6c+d divisible by 3 ?

Answer: within 20 sec.

No Solution Yet Submitted by Ady TZIDON

Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re(2): How many are divisible by 1?

| Comment 8 of 9 |

(In reply to re: How many are divisible by 1? by Charlie)

Ah, yes. I misunderstood ordered to mean that a <= b <= c <= d.

If we are just looking for the total number of solutions, then I can do this in 20 seconds.

Posted by Steve Herman on 2014-04-10 10:54:39

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