Question

I have 3 types of shapes: triangle, square or circle in the ratio 3:6:1. The triangles are either red or blue. The ratio of red triangles to blue triangles is 4:5. Given that I have 12 red triangles, how many circles are there

Answer 1

Ok first lets take care of the color
given that you have 12 red triangles and the ratio for red triangles to blue triangles is 4:5
if 12=4 than blue=5
12 times 5= 60
12 times 4 = 48
48 red and 60 blue = triangles
48+60=108
there are 108 triangles in total
now since the ratio for triangle square or circle is 
for every 3 triangles there are 6 squares and for every six squares there is one circle
t3:s6:c1
since there are 108 triangles
108/3=36
since for every 3 triangles there are 6 squares 
six times 36(amount of triangles/3)
6*36+=216
so there are 216 squares
now it says for every six squares there is one circle
therefor (the amount of squares)216/6+= 36 
we are back to 36 and there are 36 circles

Answer 2

Answer:

You will have 9 circles.

Step-by-step explanation:

The ratio of red triangles to blue triangles is 4:5  

This means that for every 4 red triangles, you have 5 blue triangles.  

And given is that you have 12 red triangles , so you would have 15 blue triangles.

Now in total you have $12+15=27$ triangles.

The ratio of triangles to circles is 3:1  

This means for every 3 triangles, you have 1 circle.  

As you have 27 triangles, we can say that there are three times as many triangles as circles.  

Hence, circle will be = $27/3=9$ circles

Therefore, you will have 9 circles.