Answer:

Step-by-step explanation:
Step one:
Given data
dimension of the rectangle
Width = 8y-1.5
Length = 1.5y+9
Required
The expression to represents the Perimeter
Step two:
the perimeter of a rectangle is expressed as

collect like terms

9 dived by 3 = 3
so he surfed for 3 hours = 1/3 of 9
and there are 6 hours left
so he spent 6 hours building a sandcastle
Area of a triangle = base x height / 2
64 = base x height / 2
(multiply 2 on both sides)
128 = base x height
then if base= 16 and height = 8 then 16 x 8 = 128
thus the base is 16 which is twice the height:8
Divide 2 from both sides
t < 5/2
Hope this helps!