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Students of three different classes appeared in common examination. Pass average of 10 students of first class was 70%, pass average of 15 students of second class was 60% and pass average of 25 students of third class was 80% then what will be the pass average of all students of three classes?
Answer & Solution
Correct Answer:
Option
D
$$\eqalign{
& {\text{Sum}}\,{\text{of}}\,{\text{pass}}\,{\text{student}}\,{\text{}}\,{\text{first,}}\,{\text{second}}\,{\text{and}}\,{\text{third}}\,{\text{class}}, \cr
& = \left( {70\% \,{\text{of}}\,10} \right) + \left( {60\% \,{\text{of}}\,15} \right) + \left( {80\% \,{\text{of}}\,25} \right) \cr
& = 7 + 9 + 20 = 36 \cr
& {\text{Total}}\,{\text{students}}\,{\text{appeared}}, \cr
& = 10 + 15 + 25 = 50 \cr
& {\text{Pass}}\,{\text{average}}, \cr
& = 36 \times \frac{{100}}{{50}} = 72\% \cr} $$
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Login(70%of10)+60%of15)+(80%of25)
7+9+20=36 this is total pass mark
Sum of Total students= 10+15+25=50
Then we can get pass averege of all students by this formula
Pass average= Total pass mark /total no of students ×%
36/50*100= 72 is the correct answer 🙏 sorry for previous ansewer the correct answer is 72 thank U
Let's calculate the total number of students and the total pass marks for all three classes:
First class: 10 students with a pass average of 70%.
Total pass marks for the first class = 10 * 70% = 7 * 10 = 70.
Second class: 15 students with a pass average of 60%.
Total pass marks for the second class = 15 * 60% = 9 * 15 = 135.
Third class: 25 students with a pass average of 80%.
Total pass marks for the third class = 25 * 80% = 20 * 25 = 500.
Now, calculate the total number of students:
Total number of students = 10 + 15 + 25 = 50.
Calculate the total pass marks for all students:
Total pass marks = 70 + 135 + 500 = 705.
Finally, calculate the pass average for all students:
Pass average = (Total pass marks / Total number of students) * 100%
= (705 / 50) * 100%
= 14.1 * 100%
≈ 74%.
Therefore, the pass average of all students from the three classes is approximately 74%.
The closest option to 74% is option A. 74%.
= (70% of 10) + (60% of 15)+ (80% of 25)
= (70/100 X 10) + (60/100 X 15)+ (80/100 X 25)
=7 + 9 + 20 = 36