A concert promoter sold 475 tickets to a rock concert. The ticket prices for different seat locations were $10, $15, and $20. The total income from the concert was $6,300. If the combined number of $10 and $15 tickets sold was 4 times the number of $20 tickets sold, how many $10 tickets were sold?

hi,

3. 12.15, you are correct.

4.2.01, your first digit is correct,

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step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.