Formulae / Changing the subject

Original post by Bryz

So what fraction do you need if the doses are the same

That gives you p

Solve for w

Reply 2

Original post by TenOfThem

So what fraction do you need if the doses are the same

That gives you p

Solve for w

sorry, i still don't understand :frown:

i am poor at maths..

Reply 3

Original post by Bryz

sorry, i still don't understand :frown:

i am poor at maths..

P is the fraction

If a child needed half an adult dose p would be 0.5

The child needs a full adult dose, so what is p

Reply 4

Original post by TenOfThem

P is the fraction

If a child needed half an adult dose p would be 0.5

The child needs a full adult dose, so what is p

Just worked it out, thanks, p = 60

BUT the next question, I was asked to make w the subject, and I am stuck halfway through it, could you please make w the subject so i can see where i am going wrong?

Reply 5

p= 3w+20/200

Subtract 20/200 from both sides and divide by 3 :smile:

20/200 = 1/10 or 0.1

Reply 6

Original post by L'Evil Fish

p= 3w+20/200

Subtract 20/200 from both sides and divide by 3 :smile:

20/200 = 1/10 or 0.1

Bit late mate :wink:

Thanks anyways!

BUT the next question, I was asked to make w the subject, and I am stuck halfway through it, could you please make w the subject so i can see where i am going wrong?

Reply 7

Original post by Bryz

Bit late mate :wink:

Thanks anyways!

BUT the next question, I was asked to make w the subject, and I am stuck halfway through it, could you please make w the subject so i can see where i am going wrong?

Can't see anything?

Reply 8

Original post by L'Evil Fish

Can't see anything?

What do you mean?

I was asked to make (w) the subject of the original equation : p = 3w + 20/200

I did most of it, but I am stuck on the last bit or have done it wrong, could you please do that with your working so I can see if I am correct/where I went wrong?

Reply 9

Original post by Bryz

I told you :tongue:

Subtract 20/200 from both sides.
Divide by 3.

Reply 10

Original post by L'Evil Fish

I told you :tongue:

Subtract 20/200 from both sides.
Divide by 3.

How does that make sence?:O

Could you show each step logically, and represent both sides please? Thanks :smile:

Also the next question after that is to :

Express A in terms of W in the following formula

3w+20/200 = A/A+12

Reply 11

Original post by Bryz

No

P does not equal 60

Btw

Your original post is VERY misleading

You should have said p=(3w+20)/200

Reply 12

Original post by Bryz

How does that make sence?

It would make sense IF your OP had been correct

But, as I say, it isn't

Reply 13

Start with w

What do you do to w to get p

Do the reverse to p to get w

Reply 14

Original post by TenOfThem

No

P does not equal 60

Btw

Your original post is VERY misleading

You should have said p=(3w+20)/200

no.wonder...

Original post by Bryz

How does that make sence?:O

Could you show each step logically, and represent both sides please? Thanks :smile:

Also the next question after that is to :

Express A in terms of W in the following formula

3w+20/200 = A/A+12

The first:

p = \frac{3w+20}{200}

Multiply by 200

200p = 3w + 20

Now subtract 20 from both sides and divide by 3.

Reply 15

Original post by L'Evil Fish

no.wonder...

The first:

p = \frac{3w+20}{200}

Multiply by 200

200p = 3w + 20

Now subtract 20 from both sides and divide by 3.

Thank you my friend!

Reply 16

Original post by TenOfThem

No

P does not equal 60

Btw

Your original post is VERY misleading

You should have said p=(3w+20)/200

Sorry!

Could you guys show each step logically for this question? :

Express A in terms of W in the following formula

3w+20/200 = A/A+12

Reply 17

Original post by Bryz

Sorry!

Could you guys show each step logically for this question? :

Express A in terms of W in the following formula

3w+20/200 = A/A+12

So, even though you are sorry, you are not willing to use the bracket keys to ask this question

Reply 18

Original post by Bryz

Sorry!

Could you guys show each step logically for this question? :

Express A in terms of W in the following formula

3w+20/200 = A/A+12

Please please use brackets.

(3w+20)/20 = A/(A+12)

Make.a.common denominator? Or multiply throughout by 20(a+12)

What do you get?

Reply 19