Answer:
A
Step-by-step explanation:
Using the recursive formula with a₁ = 5 , then
a₂ = 2a₁ - 7 = 2(5) - 7 = 10 - 7 = 3
a₃ = 2a₂ - 7 = 2(3) - 7 = 6 - 7 = - 1
a₄ = 2a₃ - 7 = 2(- 1) - 7 = - 2 - 7 = - 9 → A
I assume the solid is a "regular hexagonal prism", by which it means that the cross section is a regular hexagon with all sides and angles equal.
Also, the exact apothem is 9.5262... but we will adopt the given value of 9.5.
First lateral surface area
A1=6*side length*height=6*11*20=1320 units
Then the end areas
A2=2 faces * 6 triangles/face * [base * height (apothem) /2]
=2*6*11*9.5/2
=627 units
Total area=1320+627=1947 units
If 30% were perfect, 70% were not perfect. So we know that 70% of the total number of photographs is 210.
p(70/100)=210 multiply both sides by 100
70p=21000 divide both sides by 70
p=300
So there are 300 photographs in all.
