15-year old students a) How many 15-year old
students took part in
the survey?
(1)
b) How many more 15-year
old students than 11-year
old students spent
between 35 and 45 mins
on social media?
(1)
Total marks: 2
10 20 30 40 50 60 70 80
Time (mins)
Next Question

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?