Q1. [1] § Chapter Opening and Epigraph § 14.2 Summary
The number of red balls in a bag is 10 more than the number of black balls. If the probability of drawing a red ball at random from this bag is $\frac{3}{5}$, then the total number of balls in the bag is :
- (a) 50
- (b) 60
- (c) 80
- (d) 40
Previously asked in CBSE board exam
2025 30/4/1 Q5
Generated by claude-sonnet-4-6 · 2026-06-15 10:30 · grounding rag
Model Answer
(d) 25
Wait — let me solve: Let black balls = x, red balls = x + 10. P(red) = (x+10)/(2x+10) = 3/5 → 5(x+10) = 3(2x+10) → 5x+50 = 6x+30 → x = 20. Total = 2(20)+10 = 50.
Answer: (a) 50
Explanation
Set black balls = x, red balls = x + 10, total = 2x + 10. Use P(red) = 3/5 to form the equation and solve for x = 20, giving total = 50. Always set up a variable equation from the probability condition in such problems.
If a question refers to an image, map, graph or diagram that is not shown here, find the actual CBSE question paper on the CBSE website:
cbse.gov.in.