Leaving Cert Maths Paper 1 2013

A stadium can hold 25 000 people. People attending a regular event at the stadium must purchase a  ticket in advance. When the ticket price is €20, the expected attendance at an event is 12 000 people.  The results of a survey carried out by the owners suggest that for every €1 reduction, from €20, in  the ticket price, the expected attendance would increase by 1000 people. 

(a) If the ticket price was €18, how many people would be expected to attend?12000+(20−18)1000=14000 

(b) Let x be the ticket price, where x ≤ 20. Write down, in terms of x, the expected attendance at such an event. 

$$12000+(20− x)1000= 32000−1000x$$

(c) Write down a function f that gives the expected income from the sale of tickets for such an  event. 

$$f(x) = (32000−1000x)x$$

(d) Find the price at which tickets should be sold to give the maximum expected income.  

$$f(x) = (32000−1000x)x$$       $$f(x) = 32000−2000x = 0$$ ... $$x = €16$$

(e) Find this maximum expected income.  

$$f(x) = (32000−1000x)x$$ $$f(16) = (32000−16000)16 = €256000$$

(f) Suppose that tickets are instead priced at a value that is expected to give a full attendance at   the stadium. Find the difference between the income from the sale of tickets at this price and   the maximum income calculated at (e) above. 

$$32000 −1000x = 25000$$ ... $$1000x = 7000$$ ... $$x = 7$$       $$f(x) = (32000−1000x)x$$ ... $$f(7) =(32000−7000)7 =175000$$      Difference: €256 000 − €175 000 = €81 000

(g) The stadium was full for a recent special event. Two types of tickets were sold, a single ticket  for €16 and a family ticket (2 adults and 2 children) for a certain amount. The income from  this event was €365000. If 1000 more family tickets had been sold, the income from the  event would have been reduced by €14000. How many family tickets were sold? x = number of single tickets   f = number of family tickets   y = cost of family ticket    x+4f = 25000

$$16x+fy= 365000$$ $$16(x-4000)+(f+1000)y = 351000$$ $$16x -  64000+fy+ 1000y = 351000$$ $$16x + fy = 365000$$ __________________ $$1000y=50000$$ $$y=50$$ $$x+4f = 25000$$ $$16x+ 50f = 365000 16x+ 64f =  400000$$ ________________ $$14f = 35000$$ $$f=2500$$

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