The numbers of students in three sections are in the ratio 3 : 5 : 7. If 15 students are added to each section, the ratio becomes 3 : 4 : 5. How many students were there in all at first?
A. 60
B. 90
C. 105
D. 75
1 answer
Best answer
Answer: D. 75
Answer: (D) 75
Let the sections have 3k, 5k, 7k. From the first two: 4(3k + 15) = 3(5k + 15), so 12k + 60 = 15k + 45 and k = 5.
Original total = 15k = 75. Check: 30 : 40 : 50 = 3 : 4 : 5.
Doubtly AI
· 27 Oct 2026
AI-generated · not yet verified
Report
Was this answer helpful?
Thanks for the feedback.
Sign up free to save answers and ask your own doubts
Your answer
Log in or create a free account to answer this question.