Question

the probability of getting a defective pen from a lot of 500 pens is 1/25. Find the number of defective pens in the lot

Answer 1

P(E)=n(E)/n(s).... 1/25=n(e)/500...... n(E)=500/25..... n(E)=20

Answer 2

Probability = Favourable Observation / No . of Observation
So,
P(of getting Defective Pen) = No . of Defective Pen / Total No . of Pens
1 / 25 = No. of Defective Pen / 500
No . of Defective Pen = 500 / 25
No . of Defective Pen = 20

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