# Thread: graph of demand

1. ## graph of demand

i obtained two graphs of supply and demand by Excel, but now i hav a problem which is the supply infomation is given in terms of the actual number that supplied, but the demand is given as a percentage of the maximun possible numbers available for sale.
because i need to use Goal Seek to calculate the market price, which the two functions need to be in the same units.
Question: How can i make them in the same units????
Many thanks.

2. here is the original question :

the manufacture will not supply any bottles for less than 75p. when the price is £2.00, it will supply 30000 bottles and when the price is £3.00 it will supply 75000 bottles.

i take the price in £ and the bottles in thousand
use the points (0.75 ,0) (2,30) and (3,75 ) to get a graph of supply. Is it right?

AND the demand survey is given as the table below:

price (£) 1.5 2.00 2.50 3.00 3.50 4.00
percentage 89.46 37.60 16.54 7.05 3.80 1.56

i just used these figures got a graph of demand. If i want solve the problem I asked above, should I CHANGE the unit first or I can change later?? and HOW can i chage the unit??

3. Attached is an excel sheet with some working of your problem.

Have a look and see if you can figure out what I've done. No time to explain - exam study. I'll try to reply if I get a chance.

Hopefully it will get you on the right track.

BTW. is this high school or university economics?

4. it's university financial maths. I've never done such thing before.

it't kind of the same. but mine graphs are in separate sheets. coz they are not the same units.
how did u change the units?? you have not answend my question yet

plz try to get a chance to reply me

5. did u just multiply the percentage by 1000 to make it as the same as the unit of supply???

6. The supply graph is made up of two linear graphs. I worked out the equations for these linear graphs.

For example, to work out what quantity is demanded at price $1.5, I first find out how much is being supplied at price$1.5.

Note: $1.5 lies within the FIRST segment of the supply graph, so I plug this number into the first linear equation I worked out to find out how much is being supplied at this price. In this case, it is 18750. To find out how much is demanded at price$1.5:
18750*89.46% = 16773.75

This is what I've done in the formula in column F of the excel sheet.

HTH and GL

7. Originally Posted by stackcheddar
The supply graph is made up of two linear graphs. I worked out the equations for these linear graphs.

For example, to work out what quantity is demanded at price $1.5, I first find out how much is being supplied at price$1.5.

Note: $1.5 lies within the FIRST segment of the supply graph, so I plug this number into the first linear equation I worked out to find out how much is being supplied at this price. In this case, it is 18750. To find out how much is demanded at price$1.5:
18750*89.46% = 16773.75

This is what I've done in the formula in column F of the excel sheet.

HTH and GL
I see. Thank you very much. very appreciated.

8. last question

if i do this question by hand, and i got a quadratic equation for supply and an exponetia equation for demand. can i make these two quations equal to find the equlibrium point??

thanks

9. Originally Posted by xixihaha
last question

if i do this question by hand, and i got a quadratic equation for supply and an exponetia equation for demand. can i make these two quations equal to find the equlibrium point??

thanks
maybe. you still might need a graphical calculator to solve where these graphs cross over as the algebra might bit a bit tough?