The cost of 3 cheese sandwiches and 2 bottles of water is £7.80. The cost of 5 cheese sandwiches and 4 bottles of water is £14.20. What is the cost of: (a) one cheese sandwich? (b) one bottle of water?

sandwiches is £1.8

bottle water = £1.2

Step-by-step explanation:

Given data

let cheese sandwiches be x

and bottle water be y

3x+2y= 7.81

5x+4y= 14.202

solve 1 and 2

3x+2y= 7.81*5

5x+4y= 14.202*3

 15x+10y= 39

- 15x+12y= 42.6

        -2y = -3.6

y= 3.6/2

x=1.8

Put x= 1.8 in 1

3(1.8)+2y= 7.8

5.4+2y= 7.8

2y= 7.8-5.4

2y=2.4

y= 2.4/2

y= 1/2

Hence cheese sandwiches is £1.8

bottle water = £1.2

for the friend request.

when a figure, such as triangle (xyz) is reflected over the line y = x to create x'y'z' the x-coordinates and y-coordinates of the original image (pre-image) will be reversed for the image. (e.g., (x, y) > (y, x)) this means that the pre-image position of the x- and y-coordinates switch places which in turn provides a mirror like image of the original xyz.  

i notice that when i draw a line segment from x to x', that the points are parallel from each other -- they are exactly across from each other and do not intersect with any other points.  

yes, think i would see the same characteristic if you drew the line segment connecting y with the reflecting line and then y' with the reflecting line because of the essence of reflections. because it is a mirror image, each point was effected the same way which leads me to conclude that they same would apply to y and y'.