MATHS Q HeLp PLZ!!!!

Just wondering how to simplify ratio:

10x0.6^n-1 : 15x0.4^n-1

To get:

3^n-2 : 2^n-2

(I'm not sure which way round they go either)

And can you explain in detail please, because I'm no good with indices thank you :smile:

Reply 1

ExWunderkind

12

Original post by Yep

Just wondering how to simplify ratio:

10x0.6^n-1 : 15x0.4^n-1

To get:

3^n-2 : 2^n-2

(I'm not sure which way round they go either)

And can you explain in detail please, because I'm no good with indices thank you :smile:

What are common factors of both?

Reply 2

Yep

OP

Original post by ExWunderkind

What are common factors of both?

Erm 5?

Reply 3

ExWunderkind

12

Original post by Yep

Erm 5?

Wait sorry, I think I have mistaken the question.

Is it

[br][br]10x0.6^{n-1}

or

[br][br]10 \times 0.6^{n-1}[br][br]

Reply 4

Jkn

11

Original post by Yep

Just wondering how to simplify ratio:

10x0.6^n-1 : 15x0.4^n-1

To get:

3^n-2 : 2^n-2

(I'm not sure which way round they go either)

And can you explain in detail please, because I'm no good with indices thank you :smile:

10*(0.6)^{n-1} : 15*(0.4)^{n-1}[br]\Rightarrow 10*(6)^{n-1} : 15*(4)^{n-1}[br]\Rightarrow 10*3^{n-1} : 15*2^{n-1}

I've started you off, I'm sure you can finish! Use the property of ratios that you can multiply both sides by a number and the ratio will still be conserved. (*=times)

(edited 10 years ago)

Reply 5

ExWunderkind

12

Original post by Yep

Erm 5?

Original post by Jkn

10*(0.6)^{n-1} : 15*(0.4)^{n-1}[br]\Rightarrow 10*(6)^{n-1} : 15*(4)^{n-1}[br]\Rightarrow 10*3^{n-1} : 15*2^{n-1}

I've started you off, I'm sure you can finish! Use the property of ratios that you can multiply both sides by a number and the ratio will still be conserved. (*=times)

Yeah sorry, I misread the initial question then. Follow Jkn.

On a side note, why is latex not showing an algebraic x correctly anymore?

Reply 6

Jkn

11

Original post by ExWunderkind

On a side note, why is latex not showing an algebraic x correctly anymore?

Eh?

x

??

If you mean the "times" symbol, I've never had to use it before :lol:

Edit: I think it's because you used a decimal point :tongue:

Reply 7

ExWunderkind

12

Original post by Jkn

Eh?

x

??

If you mean the "times" symbol, I've never had to use it before :lol:

Edit: I think it's because you used a decimal point :tongue:

No the times symbol shows up fine for me:

2 \times 2 = 4

However x is showing up weird for me:

x = 4

Edit: It showed up weird in my preview, yet worked when I posted. Maybe you're right it was the decimal! Thanks :P

Reply 8

Jkn

11

Original post by ExWunderkind

No the times symbol shows up fine for me:

2 \times 2 = 4

However x is showing up weird for me:

x = 4

Edit: It showed up weird in my preview, yet worked when I posted. Maybe you're right it was the decimal! Thanks :P
No worries :smile:

Reply 9

Yep

OP

Original post by Jkn

10*(0.6)^{n-1} : 15*(0.4)^{n-1}[br]\Rightarrow 10*(6)^{n-1} : 15*(4)^{n-1}[br]\Rightarrow 10*3^{n-1} : 15*2^{n-1}

I've started you off, I'm sure you can finish! Use the property of ratios that you can multiply both sides by a number and the ratio will still be conserved. (*=times)