If 7 + y = 4 (mod 8), find the least value of y, 10 \(\leq y \leq 30\)

  • A 11
  • B 13
  • C 19
  • D 21
waec 2019mathematics

The correct answer is B. 13

7 + y = 4 (mod 8)

y = 4 - 7 (mod 8)

y = -3 + 8 (mod 8) 

y = 5 + 8 (mod 8)

y = 13

Previous question Next question