a few questions - gradient (1 Viewer)

[glen_s]

Hi,

I have a question on gradients....

I know the formula y = mx+b but how do you translate a graph into this?

e.g. a line cuts through the 'x' intercept at -3 and cuts through the 'y' intercept at +2, how would that translate into y = mx+b

ALSO

How do you work out the original sum of money of an investment.

e.g. someone had 2300 in an account for 5 years at 3% PA, what was the original some of money he put in?

THANKYOU, please help!!

 

[rama_v]

Hi,

I have a question on gradients....

I know the formula y = mx+b but how do you translate a graph into this?

e.g. a line cuts through the 'x' intercept at -3 and cuts through the 'y' intercept at +2, how would that translate into y = mx+b

ALSO

How do you work out the original sum of money of an investment.

e.g. someone had 2300 in an account for 5 years at 3% PA, what was the original some of money he put in?

THANKYOU, please help!!

m is the gradient, so you would use rise/run to find that, and then just sub it in for m. b is the y-intercept so in instance it would be +2.

You can calculate the gradient because the points are (-3,0) and (0,2)
so m = (2-0) / (0--3) = 2/3 so therfore m = 2/3
so the graph is y = (2/3) x +2

2300 after 5 years at 3% p.a. so let the original amount be x.
x(1.03)⁵= 2300
solve for x and thats the original amount.

 

[glen_s]

m is the gradient, so you would use rise/run to find that, and then just sub it in for m. b is the y-intercept so in instance it would be +2.

You can calculate the gradient because the points are (-3,0) and (0,2)
so m = (2-0) / (0--3) = 2/3 so therfore m = 2/3
so the graph is y = (2/3) x +2

2300 after 5 years at 3% p.a. so let the original amount be x.
x(1.03)⁵= 2300
solve for x and thats the original amount.

Thanks a lot for help, can you please do a little more....

I did this equation, it has co-ordinants (3,10) & (8,0)

So its rise over run was -2 and its be intercept is 16.

Is the answer y = -2x+16???

ALSO

For the other question what I meant something different, I will just give you the actual question.

"a enthusiast sells a limited edition sports car built in 1972 for $42500 which includes a profit of 35% on all costs occured.

What was profit made?"

THANKYOU AGAIN

 

[glen_s]

I think rama is offline?

Can anyone please answer my question???

 

[glen_s]

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deleted

 

[glen_s]

For the other question what I meant something different, I will just give you the actual question.

"a enthusiast sells a limited edition sports car built in 1972 for $42500 which includes a profit of 35% on all costs occured.

What was profit made?"

 

[glen_s]

Trev,

It was a multiple choice question, so I did 1.35* all the answers,

31481 * 1.35 = $42500

But if I add $14,875 to $31481 it'll give me $46356 so thats not right.

I know there is a more complicated way of doing it, but dont how????

Thanks anyway

 

[Trev]

I did this equation, it has co-ordinants (3,10) & (8,0)
So its rise over run was -2 and its be intercept is 16.
Is the answer y = -2x+16???

Yes; that is correct. Another way you could have done it is the two point formula:
(y-y₁)/(x-x₁)=(y₂-y₁)/(x₂-x₁)
(3,10) and (8,0) as (x₁,y₁) and (x₂,y₂) respectively gives:
(y-10)/(x-3)=(0-10)/(8-3)
y-10=-2(x-3)
y=-2x+16

 

[rama_v]

ALSO

For the other question what I meant something different, I will just give you the actual question.

"a enthusiast sells a limited edition sports car built in 1972 for $42500 which includes a profit of 35% on all costs occured.

What was profit made?"

THANKYOU AGAIN

Price includign 35% profit = 42500
let the price be x
so 1.35 x = 42500
so x = 42500/1.35 = 31481.48
so profit is 42500-31481.48 = $11018.52

add 11018.52 to 31481.52 just to check..you should get $42500

 

[**blu_rose**]

Price includign 35% profit = 42500
let the price be x
so 1.35 x = 42500
so x = 42500/1.35 = 31481.48
so profit is 42500-31481.48 = $11018.52

add 11018.52 to 31481.52 just to check..you should get $42500

how did u get 1.35?
dont u do something like 135%?

 

[Danni07]

1.35 is 135% in decimal form (you might put the % over 100, ie 135%/100)

 

[Casmira]

make sure to use the correct way in doing it with taxation stuff! itsn ot as simple as just decimal times money!