Computer-based learning (CBL) refers to any teaching methodology that makes use of computers for information transmission. At an elementary school level, computer applications can be used to display multimedia lesson plans. A survey was done on 1000 elementary and secondary schools of Assam and they were classified by the number of computers they had.
One school is chosen at random. Then:
Generated by claude-sonnet-4-6 · 2026-06-15 10:30 · grounding stimulus
Model Answer
Total number of schools = 1000
(i) Schools with more than 100 computers = 80
$$P(\text{more than 100 computers}) = \frac{80}{1000} = \frac{2}{25}$$
(ii) Schools with 50 or fewer computers = schools in (1–10) + (11–20) + (21–50)
= 250 + 200 + 290 = 740
$$P(\text{50 or fewer computers}) = \frac{740}{1000} = \frac{37}{50}$$
(iii) Schools with 10 or fewer computers = 250
$$P(\text{10 or fewer computers}) = \frac{250}{1000} = \frac{1}{4}$$
Source: Statistics, Probability (Empirical/Experimental Probability)
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Explanation
- Empirical probability = (Number of favourable outcomes) ÷ (Total outcomes). Here total = 1000.
- For part (ii), "50 or fewer" includes all three categories: 1–10, 11–20, and 21–50. Students often miss the 21–50 group — be careful.
- Always simplify the fraction to lowest terms; examiners check this.