WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts

2014 WAEC Further Mathematics Theory The probabilities that Kofi, Kwasi and Ama will pass a certain examination are \(\frac{9}{10}, \frac{4}{5}\)...

Further Mathematics
WAEC 2014

The probabilities that Kofi, Kwasi and Ama will pass a certain examination are \(\frac{9}{10}, \frac{4}{5}\) and x respectively. If the probability that only one of them will pass the examination is \(\frac{9}{50}\), find the :

(a) value of x ; 

(b) probability that at least one of them will pass the examination.

Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now
Explanation

(a) p(Kofi passes) = \(\frac{9}{10}\), p(Kofi fails) = \(\frac{1}{10}\)

p(Kwasi passes) = \(\frac{4}{5}\), p(Kwasi fails) = \(\frac{1}{5}\)

p(Ama passes) = x, p(Ama fails) = 1 - x.

p(only one passes) = p(only Kofi passes) + p(only Kwasi passes) + p(only Ama passes)

= \((\frac{9}{10} \times \frac{1}{5} \times (1 - x)) + (\frac{4}{5} \times \frac{1}{10} \times (1 - x)) + (x \times \frac{1}{10} \times \frac{1}{5})\)

= \(\frac{9(1 - x)}{50} + \frac{4(1 - x)}{50} + \frac{x}{50}\)

\(\implies \frac{9}{50} = \frac{9 - 9x + 4 - 4x + x}{50} = \frac{13 - 12x}{50}\)

\(\therefore 13 - 12x = 9 \implies 12x = 4\)

\(x = \frac{4}{12} = \frac{1}{3}\).

(b) p(at least one passes) = 1 - p(none passes).

p(none passes) = \(\frac{1}{10} \times \frac{1}{5} \times \frac{2}{3}\)

= \(\frac{1}{75}\)

p(at least one passes) = \(1 - \frac{1}{75}\)

= \(\frac{74}{75}\)


Report an Error Ask A Question Download App
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent
Your School's Whatsapp Group - Join Us now
Your School's Whatsapp Group - Join Us now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now