N is a positive integer having at most 4-digits. Determine the total number of values of N such that:
N is divisible by 7, and:
The sum of the digits of N is equal to 20.

There are 90 such values of N:

497
686
749
875
938
1379
1568
1694
1757
1883
1946
2198
2387
2576
2639
2765
2828
2891
2954
3269
3395
3458
3584
3647
3773
3836
3962
4088
4277
4466
4529
4592
4655
4718
4781
4844
4907
4970
5096
5159
5285
5348
5474
5537
5663
5726
5852
5915
6167
6293
6356
6419
6482
6545
6608
6671
6734
6860
6923
7049
7175
7238
7364
7427
7490
7553
7616
7742
7805
7931
8057
8183
8246
8309
8372
8435
8561
8624
8750
8813
9065
9128
9191
9254
9317
9380
9443
9506
9632
9821

Posted by Dej Mar on 2015-10-17 18:05:43