Let SSS be the smallest positive multiple of 151515 that comprises exactly 3k3k3k digits with k ‘0’s, k ‘3’s and k ‘8’s. Find the remainder when SSS is divided by 888.


Answer:

000

Step by Step Explanation:
  1. If a number is a multiple of 151515, it is a multiple of 333 and 555 both.
    We are given that SSS is the smallest positive multiple of 151515 which comprises exactly 3k3k3k digits. Also, SSS has kkk000sss, kkk333s,s,s, and kkk888s.s.s.
    Observe that SSS must end with 000 as it is a multiple of 555.
  2. The sum of all the digits of S=k×0+k×3+k×8=3k+8k=11kS=k×0+k×3+k×8=3k+8k=11kS=k×0+k×3+k×8=3k+8k=11k
    Since SSS is a multiple of 333, the sum of all its digits must be a multiple of 333.
    The smallest value of kkk such that 11k11k11k is a multiple of 333 is 333. Therefore, there are 333000sss, 333333s,s,s, and 333888sss in SSS.
    S=300338880S=300338880S=300338880
  3. The remainder when SSS is divided by 888 === Remainder of (Last 333 digits of S÷8S÷8S÷8)
    === Remainder of (880÷8880÷8880÷8)
    =0=0=0
         
  4. Hence, the remainder when SSS is divided by 888 is 000.

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