A concert is charging $5.50 for adult tickets and $4.00 for kids under 12 years of age. 70 tickets were sold fora total of $310. How many of the tickets were adult tickets and how many were sold to kids under 12?

The answer is: Number of adult tickets: 20. Number kid's tickets: 50.

Step-by-step explanation:

5.50a + 4.00k = 310

a + k = 70

a = 70 - k

5.50 (70-k) + 4.00k = 3.10

385 - 5.5k + 4k = 310

-1.5k = 310 - 385

-1.5k = - 75

k = - 75 / - 1.5 = 50

Find the number of adult tickets:

a + 50 = 70

a = 20

Proof:

5.50 (20) + 4.00 (50) = 3.10

110 + 200 = $310