Answer:
⅕
Step-by-step explanation:
x(x - 2) + x + 2x + 8 + 10 = 60
x² - 2x + 3x - 42 = 0
x² + x - 42 = 0
x² + 7x - 6x - 42 = 0
x(x + 7) - 6(x + 7) = 0
(x + 7)(x - 6) = 0
x = 6, -7(not possible)
x = 6
P(B/20th century) = x/[x(x-2) + x]
= 6/[6(4)+6]
= 6/30
= 1/5
