Problem

A bag contains three types of counter: purple squares, purple triangles and red triangles.
70% of the purple counters are triangles.
60% of the triangular counters are purple.
There are 14 red counters.
How many square counters are there?

Answer

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Answer

9 square counters in the bag.

Steps

Step 1 :Let P be the number of purple counters, T be the number of triangular counters, and S be the number of square counters. We have the following equations:

Step 2 :0.7P=0.6T

Step 3 :0.4T=14

Step 4 :Solve the second equation for T: T=140.4=35

Step 5 :Substitute T into the first equation: 0.7P=0.6(35)

Step 6 :Solve for P: P=0.6(35)0.7=30

Step 7 :Since there are 14 red triangles, there are 3514=21 purple triangles.

Step 8 :Since 70% of the purple counters are triangles, there are 3021=9 purple squares.

Step 9 :9 square counters in the bag.

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