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Xenon Maths Help Thread!

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Reply 40
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_Xenon_
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12
image.jpeg Hi how do I do part b, thanks.
Reply 41
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Zacken
22
Original post by _Xenon_
image.jpeg Hi how do I do part b, thanks.


If his height at age 20 is xx then his height at age 12 is 85100×x=⋯\frac{85}{100} \times x = \cdots
(edited 7 years ago)
Reply 42
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_Xenon_
OP
12
Original post by Zacken
If his height at age 12 is xx then his height at age 12 is 85100×x=⋯\frac{85}{100} \times x = \cdots


What's x?
Reply 43
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Zacken
22
Original post by _Xenon_
What's x?


His height at age 20.
Reply 44
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_Xenon_
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Original post by Zacken
His height at age 20.


Is it a hard question? We can't times by x when we don't know what it is!
Reply 45
Avatar for Notnek
Notnek
21
Original post by _Xenon_
Is it a hard question? We can't times by x when we don't know what it is!

It's quite a standard reverse percentages question.

Have you studied that topic? How do you usually do a question like this?
Reply 46
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_Xenon_
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12
Original post by notnek
It's quite a standard reverse percentages question.

Have you studied that topic? How do you usually do a question like this?


Not learnt reverse percentages but thanks!!
Reply 47
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Notnek
21
Original post by _Xenon_
Not learnt reverse percentages but thanks!!

Then you should probably learn the topic before trying questions.

Zacken has given you a way to do it using algebra. If you want to do it a different way then one of us can give you another method.
Reply 48
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Zacken
22
Original post by _Xenon_
Is it a hard question? We can't times by x when we don't know what it is!


I'm asking you to setup an equation involving x and then solve for x.
Reply 49
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_Xenon_
OP
12
Original post by notnek
Then you should probably learn the topic before trying questions.

Zacken has given you a way to do it using algebra. If you want to do it a different way then one of us can give you another method.


Original post by Zacken
I'm asking you to setup an equation involving x and then solve for x.


153/85 * 100 ? Will that be correct?

And yeah it is in a past paper I'm reviewing to fill in the gaps.
Reply 50
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Zacken
22
Original post by _Xenon_
153/85 * 100 ? Will that be correct?


Yes.
Reply 51
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_Xenon_
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12
Original post by Zacken
Yes.


OK thanks!!!
Reply 52
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_Xenon_
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12
Original post by Zacken
Yes.


Algebra is better imo, will try that!!
Reply 53
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Zacken
22
Original post by _Xenon_
Algebra is better imo, will try that!!


That is the algebraic method?
Reply 54
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_Xenon_
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12
Original post by Zacken
That is the algebraic method?


Nope.
Reply 55
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Zacken
22
Original post by _Xenon_
Nope.


Okay.
Reply 56
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_Xenon_
OP
12
Original post by Zacken
That is the algebraic method?


Like this

153 = 85/100 * x
15300 = 85x
15300/85 = x
120 = x
Reply 57
Avatar for Zacken
Zacken
22
Original post by _Xenon_
Like this

153 = 85/100 * x
15300 = 85x
15300/85 = x
120 = x


15300/85 is not 120.
Reply 58
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_Xenon_
OP
12
Original post by Zacken
15300/85 is not 120.


I made a mistake 😱
Reply 59
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Zacken
22
Original post by _Xenon_
I made a mistake 😱


Just an arithmetical one.

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