question on error in measurement (1 Viewer)

[yenta]

Hey if anyone out there is smart enough to do this question I'll be greatly appreciative...I'm stuck on a q in the Jacaranda Maths Quest textbook, in the chapter 2 practice exam questions. It is:

The diagram on the right shows the cross-section of a river. (U don't need to see the diagram)

a) Use two applications of Simpson's Rule to find the area of the river's cross-section. ANSWER: 292m

b) If the river flows with this cross-section for approximately 800m, calculate the volume of the river. ANSWER: 233 600m

c) The length of the river has been approximated to the neareast 100m. Calculate the maximum percentage error in calculating this volume. <- I'm stuck here. It says the answer is 6.25% but I don't know how to work it out. Can anyone help? Error in measurement is one of my weak points.

 

[misguided]

Hey i think i can help..
The length of the river is 800m.
The maximum error is 50.
Coz say for example anything over 850 would be rounded up to 900 coz its rounded by 100's
therefore you put the maximum error over the total distance
ie. 50 / 800
= 0.0625 (multiply by 100 to get %)
therefore answer is 6.25%.

Thats how i would do it... hope its right.. im sure it is tho... and i hope it helped ya....

Best of luck on tuesday......!

 

[yenta]

lol of course...it's simpler than I thought...I was trying to work it out in a more complicated way..oh well that's what a year of 2u advanced does to u

But thanks heaps misguided! Good luck to u as well

 

[misguided]

no probs glad to be of help.....!