The Student Room Group

two s2 questions

1. in the production of cd's at a factory, the proportion of faulty discs is known to be 1/5. each week 2000 discs are produced. estimate the prob that at most 349 faults discs are produced in one week. DONE this bit, got 0.0024

it costs 60p to produce a CD. a faulty disc is discarded, a non-faulty one is sold for 9.00, find the profit of the factory per week. ans=£13 200

2. a large bag of seed contains 3 varieties in the ratios 4:2:1, their germination rates are 50%, 60% and 80% respectively. show that 4/7 is the prob that a seed will germinate
Reply 1
1. Cost = 0.6x2000=1200
Revenue=(4/5)x2000x9=14400
Profit=14400-1200=13200
2. (4/7).(0.5) + (2/7).(0.6) + (1/7).(0.8) = 4/7

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