Hi guys,
Can someone please solve this question and explain the reason behind the solution. Specifically, could you explain how and the reasons behind the way you set up the equation. Thanks.
Tickets for a concert are available at two prices. The more expensive ticket is $30 more than the cheaper one. Find the cost of each type of ticket if a group can buy 10 more of the cheaper tickets than the expensive ones for $1800.
To do any problem of this type, you should identify what you are being asked for from the outset (and therefore define the necessary variables).
In this question, we're asked to find the cost of each type of ticket (cheaper and more expensive), so we might call these c and e respectively (in dollars).
From here, you need to identify each piece of mathematical information and relate it to these two variables:
:c+30=e)
This is from the fact that the more expensive tickets are $30 more than the cheap tickets.
The tricky part hereafter is that we don't know anything about the number of tickets sold, but let's say that in the statement regarding the $1800, there could be n expensive tickets sold (and therefore n+10 cheaper tickets could be sold):
:1800=ne\\(3):1800=(n+10)c)
This gives us a system of three simultaneous equations to solve. Substituting equation (1) into equation (2) gives:
:1800=n(c+30))
Transposing equations (4) and (3) respectively, then using substitution gives:
\left(1800-10c\right)=1800c\\1800c-10c^2+54000-300c=1800c\\0=10c^2+300c-54000\\0=c^2+30c-5400\\\left(c-60\right)\left(c+90\right)=0\\c=60,-90\\c>0\Rightarrow c=60\\\therefore e=60+30\\e=90)