Let's draw the diagonals of the square. The square is being divided by 4 right triangles. & these right triangles are also isosceles (the diagonals of a square intercepts each other in the middle).
The area of each right triangle = (6 x 6) / 2 = 18 yard² & the 4 right triangles => 4x 18 = 72 yd²
Combine the two equations in the right amounts to eliminate y :
-2 (2x + 3y) + (3x + 6y) = -2 (17) + 30
-4x - 6y + 3x + 6y = -34 + 30
-x = -4
x = 4
Solve for y :
2x + 3y = 17
8 + 3y = 17
3y = 9
y = 3
Here you go.................
You will want to subtract the amount he ran on Monday from the amount on Tuesday. In order to subtract fractions, we must set them to the same denominator (bottom number). In order to do this, we must multiply 3/5 by 6/6 (the denominator on tuesday) which gets us 18/30. Then, for Tuesday, we must multiply 2/6 by 5/5 (the denominator on Monday) which is 10/30. Now, we can do Monday-Tuesday, 18/30-10/30 which gets us 8/30, if we simplify this, we get 4/15 :)
