Urgent gcse maths question for tomorrow's exam - help please!

[LightingCandles]

We cannot understand why the answer is 3:4 and the numbers have seemingly flipped?
Many thanks!

It's 4:3 though surely???! I don't understand.

Rearranging the equation gets you to 4c=3d so c/d = 3/4

5c + d = C + 4d
4c + d = 4d
4c = 3d
C = 3d/4
C/d = 3/4

4 x c = 3 x d

So C could be 3 and D could be 4

@MadamBuxton

Rearranging the equation gets you to 4c=3d so c/d = 3/4

See the numbers have flipped! Why is it not 4:3??

4c = 3d so c is 3/4 of d

Photo

4C = 3D

Rearrange equation
The ratio of c over d it other words C:D Is 3/4 or 3:4

Divide left by d and right by d
Divide left by 4 and right by 4

Does that help?

It’s just a case of rearranging the equation to give you c/d, which is just another way of expressing c:d

You have to do the same thing to each side to make the equation balance. So start by taking away d from each side:
5c +d - d = c + 4d - d.
Which gives you 5c = c + 3d

Then take c away from each side
5c - c = c + 3d - c
Which gives 4c = 3d

If you rearrange, you get 4c=3d, or c=3/4 d. So whatever c is in your ratio, it has to be 3/4 of d. The simplest ratio where c is 3/4 of d is 3:4

4c has to equal 3d, so let’s say they both are the number 12 because 12=12 is true. So 4c=12, therefore c is 3. And 3d=12, therefore d is 4.

They aren’t flipped, you’re confusing the digits in front of the letters as the solution for what is c and d when they are just a multiplication being applied to the letters.

4 piles of something= 3 piles of something else
think of an example...

4 piles of 6 = 3 piles of 8
4x6=3x8
so if 6 is c and 8 is d
the ratio is 6:8 or 3:4

@jytdtysrht

Photo

Ah this makes sense, I think the typing syntax is hard to visualise.

So it's effectively 4(c over d) which then allows to divide by four.

Cool cool.

Thank you!

Dc says give MN a medal!

Thank you everyone!

If 4c = 3d

Then if c is 3, d would be 4

i.e. 4 x 3 = 3 x 4

So c/d = 3/4

Alternatively use the numbers you have there to see why it’s not correct. So if 4:3 then c would be 4 and d would be 3. When you put the numbers back into the equation it becomes 4x4 = 3x3, which would be 16=9 which is not true. Hope it helps! Always check by putting your answers back into the original equation is a pro exam tip

Hi Miss Candles,
You should not be asking the internet for help! Try and do it yourself or go to your teacher for help. You are not learning anything this way.

We essentailly forgot d =d/1
We are idiots!

@xxrukaiyasmumxx

Hi Miss Candles, You should not be asking the internet for help! Try and do it yourself or go to your teacher for help. You are not learning anything this way.

Yh we did try and do it ourselves. Teacher not gonna help at 9pm and exam is tomorrow. We tried Google, but as I stated earlier, we essentially forgot one step. That's what the Internet is for. But thanks for your contribution.

God I'm glad my maths GCSE is 10 years in the past. I've no idea what any of this even means anymore