Answer:
A
Step-by-step explanation:
Length : 
Perimeter: 
Perimeter = 2(Length + Width)
15x + 17y = 2(
+ Width)
15x + 17y = 7x + 14y + 2(Width)
15x + 17y -7x -14y = 2(Width)
8x + 3y = 2(Width)
Width = 
Width = 4x + 3y/2
I suppose that the expression you wanted to write is

. If so, then we have:
The formula is base x height = volume so 6 x 4 = 24
I hope that helps
A+b=6.1 ---(1)
a-b=1.6 ---(2)
(1)+(2); 2a=7.7
then a=3.85
so b=a-1.6 = 3.85-1.6 = 2.25
so that the two numbers are 2.25 and 3.85
Ratio and proportion
x/300=67/100
cross multiply
100x= 20100
x= 201 students
hope this helps