How does the medium affect the amplitude of sound?

Acompany manufactures three types of cabinets. it makes 110 cabinets each week. in the first week, the sum of the number of type-1 cabinets and twice the number of type-2 cabinets produced was 10 more than the number of type-3 cabinets produced. the next week, the number of type-1 cabinets produced was three times more than in the first week, no type-2 cabinets were produced, and the number of type-3 cabinets produced was the same as in the previous week.

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)

If the tip varies directly with the number of guest which equation represents between the tip, t, and the number of guest, g?