Answer:
25.
Step-by-step explanation:
I am assuming you only mean the small triangles, not the composite ones.
The second triangle set has 3 triangles on bottom row and 1 on the top - total 4.
The 3rd triangle set has 5 triangles on the bottom , 3 on the next up and 1 on the top - total 9
Following the pattern 4th set will have the number of triaNGLES
7 + 5 + 3 + 1 = 16.
So the 5th will have 9 + 7 + 5 + 3 +1 = 25 triangles.
Please refer to the above attachment
The total cost would be:
$20 = two people- 2*20=40$
20 = guest
20*20=
400 would be the cost
39/7
7 can fit into 39 as a whole 5 times
you then have 4 left over
5 4/7
