Answer:
Probability weightlifter hurts his back = 0.3875 i.e 38.75%
Step-by-step explanation:
Probability of using right body form = 75%
Probability of using bad body form : 1 - Prob (right body form) = 1 - 75% = 25%
Probability of getting injured if right body form = 20%
Probability of getting injured if using bad body form = 95%
Prob (Right body form & injury) or Prob (wrong body firm & injury)
(0.75) (0.20) + (0.25) (0.95)
0.15 + 0.2375
= 0.3875 i.e 38.75%