Tuesday, March 3, 2015

[Pri20150302FCW] The Cost of Fish and Chicken

Question

Solution



The ratio of the cost of fish to that of chicken is 1.5 : 1 or 3 : 2.  I choose this nice whole number ratio and write them in triangle units.  You can choose draw any shape you want to surround the ratio unit actually.  Multiplying by 3 and by 4 (the numerical dollar costs), we obtain 17 triangle units equal to 76.50.  From here we can divide by 17 to get the equivalent of 1 triangle unit, and then multiply by 3 to get the equivalent of 3 triangle units.

Ans: 1 kg of fish costs $12.50



Commentary

Once again my Ratio Units method solves this problem quickly and you can use this method to also present the answer in a matter that even the teacher who is marking this can understand J.  

1 comment:

  1. 3 x 4.50 is actually 13.50. Great simultaneous-equations riddle.

    ReplyDelete