Answer:
(a) 7.6%
(b) 46.2% 42.4%
Step-by-step explanation:
(a)According to the definition of Continuous probability distribution



⇒ 0.19 × 0.4 = F(69.2) - F(68.8)
⇒ F(69.2) - F(68.8) = 0.076
⇒ 7.6%
(b) Given F(69) = 0.5



⇒ 0.19 × 0.2 = F(69) - F(68.8)
⇒ F(68.8) = 0.5 - 0.038 = 0.462
⇒ 46.2%



⇒ 0.19 × 0.4 = F(69) - F(68.8)
⇒ F(68.8) = 0.5 - 0.076 = 0.424
⇒ 42.4%
B > -21 is i think you answer.