BOB,Ratio for October 20, 2009

The picture I chose was the "Crayon Line Up".

Part to Part Ratios:

Shades of green to purple = 3:1
Gold to shades of blue = 1:3
Shades of pink to silver = 2:1

Part to Whole Ratios:

Shades of blue to total = 3:12
Purple to total = 1:12
Shades of pink to total = 2:12

Three Part Ratios:

Gold to shades of green to silver = 1:3:1
Shades of pink to shades of blue to orange = 2:3:1
Purple to gold to shades of green = 1:1:3

Converting the ratio to a fraction, decimal, percent:

Shades of green to total = 3:12 = 3/12 = 0.25 = 25 %
Tip: to get the percent, multiply the decimal by 100 and to get the decimal you divided the numerator by the denominator.

Simplifying the Ratio:

Shades of green : total = 3:12 = 1:4 (simplified) or shades of green/total = 3/12 = 1/4 (simplified)
* To simplify the ratio, I divided 3 by 3 to get 1 and I then divided 12 by 3 to get 4 so my simplified ratio is 1:4 or 1/4.

Questions:

What would the new ratio be of the shades of pink to total crayons if it was simplified?

Express the shades of pink to silver crayons as a fraction, decimal, and percent.

If the amount of each color was doubled what would be the new ratio of the shades of blue to shades of pink and what would be your new total of crayons?


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BOB: Part 2

The mistakes I made on my test were:

• I didn't put some of my answers in lowest terms
• I didn't read the questions carefully
• I didn't show how I got my answer using ratio related strategies (ratio tables)

One of the questions I got wrong was:

3. A normal deck of playing cards has 52 cards in four suits (club, diamonds, hearts, and spades) of 13 cards each. Two of the suits are black and two suits are red. The ratio of red cards to the whole deck is

a) 1:1 b) 1:2 c) 2:3 d) 2:4

My answer for this question was letter d) 2:4.The correct answer was b) 1:2. I got this question wrong because I didn't put my answer in lowest terms.

What I need to do for my next test is:

• read the questions carefully
• show my work using ratio tables, etc.
• highlight the keywords in the questions (word ratio)
• use effective strategies to answer the questions
  

Two questions that gave me difficulty were:

7. A rapid transit train has 39 passengers on it as it starts its run. At the first stop 12 passengers get off and 18 passengers get on. What is the ratio of the number of passengers who were on the train as it arrived in the first station to the number who were on the train when it left the first station? Express your answer in lowest terms.

a) 2:3 b) 13:15 c) 18:12 d) 27:39

8. A picture frame has a width to length ratio of 5:7. If the width of the photo is 9cm, the length of the photo is

a) 11cm b) 12.6cm c) 14cm d) 16cm

Please answer these two questions in the comment section.