Answer:
[tex]\left\{\begin{array}{l}x+y=50\\3x+4y=170\end{array}\right.[/tex]
30 triangular tiles and 20 square tiles
Step-by-step explanation:
A triangular tile has three sides, a square tile has 4 sides.
Let x be the number of triangular tiles and y be the number of square tiles. A set of triangular and square tiles contains 50 pieces, then
x+y=50
There are 3x sides in all triangular tiles and 4y sides in all square tiles. The set of triangular and square tiles contains 170 sides, so
3x+4y=170.
Hence, the system of two equations is
[tex]\left\{\begin{array}{l}x+y=50\\3x+4y=170\end{array}\right.[/tex]
From the first equation
[tex]x=50-y[/tex]
Substitute it into the second equation:
[tex]3(50-y)+4y=170\\ \\150-3y+4y=170\\ \\y=170-150\\ \\y=20[/tex]
Thus,
[tex]x=50-20=30[/tex]
