Answer:
Below.
Step-by-step explanation:
To find the number of students in each grade you multiply the marks by the frequency density. The number of students is given by the area under the rectangles.
So to find the number of students with grade U (< 160) it is:
120 * 0.2 + 40*0.5
= 24 + 20
= 44.
The number for Grade E
= (200 - 160) * 0.5
= 40 * 0.5
= 20.
The others can be found in the same way.
Probability that a student will play both is 7/30
Step-by-step explanation:
Total students = 30
No. of students who play basketball = 18
Probability that a student will play basketball = 18/30
= 3/5
No. of students who play baseball = 9
Probability that a student will play baseball = 9/30
= 3/10
No. of students who play neither sport = 10
Probability that a student will play neither sport = 10/30
= 1/3
To find :
Probability that a student will play both = p(student will play both)
No.of students who play sport = 30 - 10
= 20
Out of 20 students 18 play basketball and 9 play baseball.
So, some students play both the sports.
No. of students who play both sports = 18 + 9 - 20
= 7
p(student will play both) = 7/30
Probability that a student will play both is 7/30
