Question

There are 644 boys and 520 girls in a school. The probability that a boy is chosen at random studies French is 3/7. The probability that a girl is chosen at random studies French is 5/8.

a) Work out the number of students in the school who study french
b) What is the probability, as a fraction, that a student chosen at random from the whole school does NOT study French

Answer 1

a. 601

b.

`(563)/(1164)`

Explanation:

a. The number of students in the school who study french:

The number of boys who study french + The number of girls who study french:

= (3÷7)×644+(5÷8)×520

= 601

b. the probability that a student does NOT study French :

= P(boy does not study french) + P(girl does not study french)

`=((644)/(1164) ) (1-(3)/(7) )+((520)/(1164) )(1-(5)/(8) )\\\\= (563)/(1164)`