A sociology teacher asked her students to complete a survey at the beginning of the year. One survey question asked, "How responsible are you?" Another question asked, "How many
siblings do you have?"
The probability that a student is responsible is 0.4, the probability that a student has 0
siblings is 0.45, and the probability that a student is responsible and has 0 siblings is 0.1.
What is the probability that a randomly chosen student is responsible or has 0 siblings?