Tuesday, November 11, 2014

Angelica's Proportion Problems


1) If 5 pencils cost 20 cents, how much would 15 pencils cost?


Let x be the cost of pencils (15 of them)
Word ratio, ratio table, find x (cross product)


The cost of 15 pencils, would be 60 cents.


2) Darrell drove 187 miles in 3 hours. What was Darrell's average rate of speed in miles per hour?

Let x be the average rate of speed in one hour
Word ratio, ratio table, find x (cross product)


Darrell's average speed rate in an hour is  62.3 miles.
A word problem for you:

The ratio of 7th graders to 8th graders participating in the science fair is 4:3. There are 18 eighth graders participating in the science fair. How many seventh graders are there?

2 comments :

  1. UnknownNovember 12, 2014 at 5:32 PM

    The answer for your question is:
    ~There would be 24 7th graders. (I got the answer by doing cross multiplication.)

    ReplyDelete
  2. UnknownNovember 14, 2014 at 6:29 AM

    7th graders: 8th graders
    4 : 3
    x : 18

    3(x) = 4(18)
    3x = 72
    3x/3 = 72/3
    x = 24

    There are 24 7th graders.

    ReplyDelete