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# Ratios, rates, and proportions — Harder example

Watch Sal work through a harder Ratios, rates, and proportions problem.

## Want to join the conversation?

• I am seriously losing hope as I watch more complex videos and do more complex math problems
• So, real quick... without writing and quickly using your head (not a calculator) you can figure out this one!
To make this easier to see, simply take his ratio in the problem (1cm = 20ft) and square it out. Yes, he did this, but wrote a lot. All you need to write down during the test is basically the 20 (if you need to see it to remember it is there). It is 400 because 2 squared is 4 (then put the zeros back in place to make it 400)
Next, we already see that 400 square feet is what 1 pound will cover. Under the entire field, there are 180 sections of 400 square feet. that's 180lbs. Done and only 5 seconds out of your 55 minutes (or whatever section this is in)! 😊
If you have a mind for patterns, ratios, rates and proportions are easy. But if not, that's ok because often times you will have the tendency to be able to handle many more types of problems I will never be able to ever figure out! 😉
• this question is troubling me:
There are 78 biscuits in a box. Some are salty and the rest are sweet. Which of the following could be the ratio of salty to sweet biscuits in the box?
A) 3:4 B) 4:1 C) D) 5:8 E) 1:3
• E has to be the answer. Unless the biscuits are broken and you are considering bits of pieces of biscuits, the only number in the given options that divides 78 perfectly is the number 3. For example 78/3=26. However, 78/4=19.5 and since there aren't half biscuits when considering ratios of salty and sweet biscuits, all answers with 4 is wrong eliminating A, and B. C is not the answer because both 5 and 11 does not result in an integer. 78/5=15.6 and 78/11=7.09 eliminating C, thus since D has 5 as well, it cannot be the answer. Also the 8 in D results in a 9.75 which does not make sense. Therefore, the only reasonable answer is E containing 1 and 3, both resulting in a integer when dividing 78.
• how is one minute enough to answer this on the sat? The hardest part isn't solving it. The hardest part is just trying to understand what that question is asking of you.
• It took like 10 sec to solve this..
• For this question, instead of doing all that work to get 180 pounds, wouldn't have it been much simpler to realize that for every square centimeter, it is 400 square feet, and for every 400 square feet, it's one pound of seed, so then you would need 180 pounds of seed?
• Dam I guess everyone thought it was 9
• same here
• Guys i'm new here
right now i just need some encouraging words
i'm beginning to loose hope on sat
• what's sat
• Will they give you the conversions on the SAT or will we have to memorize the actual conversations?
• I think they usually provide the conversions in parenthesis. The only thing I think you would have to know is time. For examples, 60 seconds in a minute and 60 minutes in an hour.
• i thought the answer would be 9 since x= number of pounds of seed she need to cover the entire field 3600/x=400/1 400x=3600 x=9pounds
• your mistake is in the conversion of the units :
if 1cm=20ft you cannot convert 180cm^2 to ft^2 by simply replacing cm with 20ft then doing 180*20=3600
and that's because 1cm is different than 1cm^2
if 1cm=20ft
1cm^2=400ft^2
which means that 180cm^2=72 000ft^2(not 3600)
NOW if you try your method:
72000/x = 400/1
400x = 72000
x = 72000/400 = 180
(1 vote)
• not going to lie but when I read the question before he solved anything I thought the answer was 9 because I divided 180 by 20 and after he solved it it made much more sense because, with my answer, the field would be small compared to the right answer.