That’s the correct answer
The probability that a student selected at random majors in engineering is 30% which is 0.3.
The probability that the student both majors in engineering and play club sports is 10% which is 0.1.
For a student who is selected at random to be one who majors in engineering, there are two possible ways.
The student majors in engineering OR the Student both majors in engineering and plays club
The Probabilty that the student majors in Enginnering =
The probability that the student majors in engineering plus the probability that Student both majors in engineering and plays club sport
= 0.3+0.1= 0.4
Divide 28 by 3 and count how many are left over.
28 / 3 = 9 1/3
So each boy had 9 toy cars, and because you can't have 1/3 cars, you round 1/3 to 1. So there was 1 left over car.