Answer:




Step-by-step explanation:
Given:



Solving (a): The value of y
From the given parameters, we understand that

Substitute values for RS, ST and RT

Collect Like Terms


Divide both sides by 2


Solving (b):
<em>The value of RS</em>
Substitute 6 for y in 



<em>The value of ST</em>
Substitute 6 for y in 



<em>The value of ST</em>
Substitute 6 for y in 



Each friend gets half a piece of construction paper
In plain and short, we simply will divide the whole amount of 2.5lbs by (7+2+5), and then distribute accordingly to each component,

The first part is 1325
10 x 35=350
15 x 65=975
The you add them which equals 1325