Find the sum of all three -digits natural numbers which are divisible by 13.

Asked by mahtosunita1234 | 26th Oct, 2019, 09:07: PM

Expert Answer:

. T h e space f i r s t space 3 space d i g i t space n u m b e r space d i v i s i b l e space b y space 13 space i s space 104 space a n d space l a s t space 3 space d i g i t space n o. space d i v i s i b l e space b y space 13 space i s space 988
a equals 104 comma space a subscript n equals 988 space a n d space d equals 13
a subscript n equals a plus left parenthesis n minus 1 right parenthesis d
rightwards double arrow 988 equals 104 plus left parenthesis n minus 1 right parenthesis 13
884 equals left parenthesis n minus 1 right parenthesis 13
68 equals n minus 1
n equals 69
T h e r e f o r e comma space t h e space s u m space o f space a l l space 3 space d i g i t space n a t u r a l space n o s. space d i v i s i b l e space b y space 13 space i s
S subscript 69 equals 69 over 2 left parenthesis 2 cross times 104 plus 68 cross times 13 right parenthesis equals 37674

Answered by Renu Varma | 27th Oct, 2019, 12:33: AM