If b = 50

11$50$ + 7$50$ + 15 + 50
550 + 350 + 15 + 50
= 965

If b = 99

11$99$ + 7$99$ + 15 + 99
1089 + 693 + 15 + 99
= 1896

If b = 1001001

11$1001001$ + 7$1001001$ + 15 + 1001001
11011011 + 7007007 + 15 + 1001001
= 19019034