Решение:

5(c+3) ÷ 6 = 8(10-c) ÷ 6

5c + 15 ÷ 6 = 80 - 8c ÷ 6

Multiplying both sides of the equation by 6 to eliminate the fractions:

5c + 15 = 48 - 8c

Adding 8c to both sides:

13c + 15 = 48

Subtracting 15 from both sides:

13c = 33

Dividing both sides by 13:

c = 33/13
c = 2.54 (rounded to two decimal places)

Therefore, the solution to the equation is c = 2.54.