DAT Achiever Math Question.......I dont get this one

[Toothguy80]

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There are museum tickets,
$9 for adults
$6 for retiree
$2.50 for children under 12

What should the minimum generated gross income be from child tickets if the total amount money made was $210 and 15 adult tickets had been sold.

😱😕

 

[jaz129]

If the answer is asking for the minimum number of child tickets needed to gross a total $210 then after subtracting the income from the adults(210-135) you are left with 75 between children and retiree. Then you have to figre out the highest number that 6 is a factor of after subtracting the 2.50 for a child ticket. It would never be a decimal so justgot -5 ,-10, -15 Soooooooooo...the only number is 60..which you get after selling six child tickets.
75-15.0=60
Anyway I don't know if this is right but that is how i would solve it.

 

[Nasem]

1) look at whats given
9 * 15 = $135 from adults only
210 - 135 = $75 from retiree and children

2) my favorit method, trial and error

a) divide: 75 / 6 = 12.5,
so, use the whole number 12 and multiply: 12 * 6 = 72, meaning you only have 3 dollars left for a child ticket (wrong because you will still have 50 cents left over)

b) now try 11, so multiply: 11 * 6 = 66,
75 - 66 = 9
9 / 2.5 = not a whole number, wrong again

c) finally, try 10, so multiply: 10 * 6 = 60
75 - 60 = $15
15 / 2.5 = 6 (BINGO), 6 tickets for children is the minimum number that could have been sold

 

[jaz129]

Ok he explained it better, but atleast I now know that I was right...🙂 for my own sake