[Script Info]
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[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.43,Default,,0000,0000,0000,,I have three word problems in this video.
Dialogue: 0,0:00:02.43,0:00:05.89,Default,,0000,0000,0000,,What I want to do in this video is not solve the word problems,
Dialogue: 0,0:00:05.89,0:00:10.15,Default,,0000,0000,0000,,but setup the equation that we could solve to get the answer to the word problem.
Dialogue: 0,0:00:10.15,0:00:13.60,Default,,0000,0000,0000,,What we are essentially going to do is setup the proportionality for the word problems.
Dialogue: 0,0:00:13.60,0:00:14.91,Default,,0000,0000,0000,,So In this 1st problem
Dialogue: 0,0:00:14.91,0:00:18.93,Default,,0000,0000,0000,,we have 9 markers cost $11.50. And then they ask:
Dialogue: 0,0:00:18.93,0:00:22.24,Default,,0000,0000,0000,,How much will 7 markers cost.
Dialogue: 0,0:00:22.24,0:00:31.33,Default,,0000,0000,0000,,Now, let's just set X to be equal to our answer, where X is equal to the cost of 7 markers.
Dialogue: 0,0:00:31.33,0:00:34.47,Default,,0000,0000,0000,,The way to solve a problem like this is to setup two
Dialogue: 0,0:00:34.47,0:00:36.33,Default,,0000,0000,0000,,ratios and set them equal to each other.
Dialogue: 0,0:00:36.33,0:00:38.82,Default,,0000,0000,0000,,So you could say that the ratio of 9 markers
Dialogue: 0,0:00:38.82,0:01:10.58,Default,,0000,0000,0000,,to the cost of 9 markers; 9/ 11.50 = 7/ X
Dialogue: 0,0:01:10.58,0:01:21.05,Default,,0000,0000,0000,,This is a completely valid proportion here.
Dialogue: 0,0:01:21.05,0:01:23.47,Default,,0000,0000,0000,,You could solve this to figure out how much those
Dialogue: 0,0:01:23.47,0:01:25.32,Default,,0000,0000,0000,,7 markers will cost.
Dialogue: 0,0:01:25.32,0:01:58.55,Default,,0000,0000,0000,,You could have 11.50/9 = X/7 .This is also a valid ratio.
Dialogue: 0,0:01:58.55,0:02:01.65,Default,,0000,0000,0000,,You could also think about ratios in other ways
Dialogue: 0,0:02:01.65,0:02:11.40,Default,,0000,0000,0000,,You could say, that the ratio of 9 markers to 7 markers,
Dialogue: 0,0:02:11.40,0:02:22.93,Default,,0000,0000,0000,,is going to be same as the ratio of their cost
Dialogue: 0,0:02:22.93,0:02:42.75,Default,,0000,0000,0000,,9/7 = 11.5/X or 7/9 = X/11.5
Dialogue: 0,0:02:42.75,0:02:51.06,Default,,0000,0000,0000,,So all of these would be valid proportion.
Dialogue: 0,0:02:51.06,0:02:54.93,Default,,0000,0000,0000,,Sp let's do this problem now. 7 aples cost $5.
Dialogue: 0,0:02:54.93,0:03:02.17,Default,,0000,0000,0000,,How much can I buy with $8.
Dialogue: 0,0:03:02.17,0:03:11.20,Default,,0000,0000,0000,,How many apples - let's call that X. We need to solve for X
Dialogue: 0,0:03:11.20,0:03:13.14,Default,,0000,0000,0000,,So we have the ratio between number
Dialogue: 0,0:03:13.14,0:03:34.93,Default,,0000,0000,0000,,of apples and cost of the apples - 7/5= X/8
Dialogue: 0,0:03:34.93,0:03:42.80,Default,,0000,0000,0000,,In this first situation the unknown was cost, in this example
Dialogue: 0,0:03:42.80,0:03:49.51,Default,,0000,0000,0000,,the unknown is number of apples.We can do all the different
Dialogue: 0,0:03:49.51,0:04:15.19,Default,,0000,0000,0000,,scenarios as above. we could say 7/X = 5/8
Dialogue: 0,0:04:15.19,0:04:19.17,Default,,0000,0000,0000,,Now lets do the last one. We have a cake recipe for
Dialogue: 0,0:04:19.17,0:04:32.66,Default,,0000,0000,0000,,5 people requires 2 eggs. How many eggs? So we want to know how many eggs?
Dialogue: 0,0:04:32.66,0:04:35.76,Default,,0000,0000,0000,,We will call how many eggs, which we
Dialogue: 0,0:04:35.76,0:04:45.22,Default,,0000,0000,0000,,need to find out as X, we can call it anything Y,A,B,C anything.
Dialogue: 0,0:04:45.22,0:04:56.67,Default,,0000,0000,0000,,So you could say the ratio of people to eggs is constant.
Dialogue: 0,0:04:56.67,0:05:13.40,Default,,0000,0000,0000,,We have 5 people for 2 eggs - 5/2 = 15/X
Dialogue: 0,0:05:13.40,0:05:38.87,Default,,0000,0000,0000,,Or you could say the ratio between 5/15 = 2/X
Dialogue: 0,0:05:38.87,0:05:46.93,Default,,0000,0000,0000,,All of these we setup the proportion and we can
Dialogue: 0,0:05:46.93,0:05:50.93,Default,,0000,0000,0000,,solve for X and get the answer.