# Tutorials > 10 Days of Statistics > Day 8: Pearson Correlation Coefficient II
# Find the Pearson correlation coefficient
#
# https://www.hackerrank.com/challenges/s10-mcq-7/problem
# challenge id: 21709
#

# explication:
#   3*x + 4*y + 8 = 0  ⟹  y = -3/4 * x - 2    ⟹  b = -3/4 = ρ σy/σx
#   4*x + 3*y + 7 = 0  ⟹  x = -3/4 * y - 7/4  ⟹  b = -3/4 = ρ σx/σy
#   (-3/4)² = ρ²  ⟹  ρ = ± 3/4
#   b < 0  ⟹  ρ = - 3/4

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