136

Part of 1970 All Soviet Union Mathematical Olympiad

Problems(1)

ASU 136 All Soviet Union MO 1970 m same digits in 5 n-digit numbers

Source:

n

-digit binary numbers. For each two numbers their digits coincide exactly on

m

places. There is no place with the common digit for all the five numbers. Prove that

2/5 \le m/n \le 3/5

number theoryDigits