Answer:
80 parrots were purchased.
Step-by-step explanation:
Let the total number of parrots be k.
If 20% (or 20/100 = 1/5) flew away and 5% (5/100 = 1/20) died, the remaining parrots will be k – (¹/₅k + ¹/₂₀k) = k – ¼k = ¾k.
Of the remaining, 45% (or 45/100 = 9/20) were sold, which means the total number of sold parrots will be ¾k × ⁹/₂₀ = ²⁷/₈₀k.
The remaining parrots = ¾k – ²⁷/₈₀k = ³³/₈₀k = 33
k = 33 × ⁸⁰/₃₃ = 80 parrots were purchased.

Substituting into the second expression,
Answer:
x =
will be the expression.
Step-by-step explanation:
In this question an expression has been given which represents the relation between average cost C and number of T shirts (x) manufactured.
We have to solve this expression for the value of x (number of T-shirts) in terms of C.
C = 5x + 410x
C = 415x
x = 
Therefore, x =
will be expression showing the number of T-shirts in terms of average cost.