Final answer:
The best student got 85 marks when the average mark for three pupils is 68 and their marks are in the ratio of 5:4:3.
Step-by-step explanation:
The question seeks to determine how many marks the best student got if the average mark of three pupils is 68 and their marks are in the ratio of 5:4:3.
- Let's call the total marks of the three pupils x.
- Since their average is 68, we can write the equation x / 3 = 68.
- Solving this equation, we find that x = 68 * 3 = 204.
- Now, let's assign the ratios to the students: the best student has 5 parts, the second has 4 parts, and the third has 3 parts.
- The total parts are 5 + 4 + 3 = 12 parts.
- To find the value of one part, we divide the total marks by the number of parts: 204 / 12 = 17.
- Now, we can determine the marks for the best student by multiplying 17 (the value of one part) by 5 (the number of parts for the best student): 17 * 5 = 85.
Therefore, the best student got 85 marks.