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Mumtaaz

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It takes Karl 15 minutes to clean his room. It takes Jesse at least twice as long to clean her room. Which inequality expresses this relationship, if x is equal to the amount of time it takes Jesse to clean her room?

a. 15 < 2x
b. 15 < x/2
c. 15 > 30x
d. 30 > 2x
 
Mumtaaz said:
It takes Karl 15 minutes to clean his room. It takes Jesse at least twice as long to clean her room. Which inequality expresses this relationship, if x is equal to the amount of time it takes Jesse to clean her room?

a. 15 < 2x
b. 15 < x/2
c. 15 > 30x
d. 30 > 2x
Click to expand...
What do you think?
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Mumtaaz said:
It takes Karl 15 minutes to clean his room. It takes Jesse at least twice as long to clean her room. Which inequality expresses this relationship, if x is equal to the amount of time it takes Jesse to clean her room?

a. 15 < 2x
b. 15 < x/2
c. 15 > 30x
d. 30 > 2x
Click to expand...
x represents how long it takes Jesse to clean her room. We quickly see that it takes Jesse at least 30 minutes to clean her room. So how can we compare 30 and x? Are any of the choices equivalent to what you got?

Choice a: 15 < 2x. I would rewrite this as 2x>15. This says that twice the time it takes Jesse to clean her room (remember that x = how long it takes Jesse to clean her room) is more than 15 minutes. Is this true? If it is, can you make a stronger statement?
Choice b. 15 < x/2 Same as x/2 > 15. If you divide the time it takes Jesse to clean her room by 2 you will get more than 15. Is this true? If it is, can you make a stronger statement?

Can you do the same with the others choices?
 
Jomo said:
x represents how long it takes Jesse to clean her room. We quickly see that it takes Jesse at least 30 minutes to clean her room. So how can we compare 30 and x? Are any of the choices equivalent to what you got?

Choice a: 15 < 2x. I would rewrite this as 2x>15. This says that twice the time it takes Jesse to clean her room (remember that x = how long it takes Jesse to clean her room) is more than 15 minutes. Is this true? If it is, can you make a stronger statement?
Choice b. 15 < x/2 Same as x/2 > 15. If you divide the time it takes Jesse to clean her room by 2 you will get more than 15. Is this true? If it is, can you make a stronger statement?

Can you do the same with the others choices?
Click to expand...
My Initial answer was a, because I knew that it took her 30 mins to clean her room, so I thought 2(15) = 30 and the expression would then be true.

c) 15 > 30x , this means 30 is multiplied to the amount of time it takes to clean her room and that 15 is greater than the answer for it, I think that is wrong.
d) 30 > 2x , this means that however long it takes to clean her room multiplied by 2, is less than 30 (or equal to, I forgot to include the equal sign)
 
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