Question

if a plane can travel 490 mph with the wind and 430mph against the wind, find the speed of the plane in still air

Answer 1

hello deano8677 :)

make a diagram first.

Answer 2

i made one and it doesnt seem to be helping me
:(

Answer 3

use algebra! :DDD

upstream speed = speed of plane (still) - speed of current
downstream speed = speed of plane (still) + speed of current

need more hints? or are you good? :D

Answer 4

(490+430)/2=460mph

Answer 5

well ya i kinda do need more hints lol

Answer 6

that was more confusing to me than the ?

Answer 7

let x = speed of plane (still) and c = current

downstream speed = 490 mph = x + c
upstream = 430 = x - c

x + c = 490
x - c = 430

what about now? getting it? :DDD

Answer 8

so it would be 460?

Answer 9

hmmm remember you're looking for speed of plane (still) which is x...you use systems to cancel the speed of current (which is c)

so you add the system to cancel c

Answer 10

so my formula is x-c(X) + c=490

Answer 11

wait..what did you do?

x + c = 490
x - c = 430

add the 2 equations

(x+x) + (c - c) = (490 +430)
2x + 0 = 920

getting it now?

Answer 12

im sorry my computer froze on me

Answer 13

so wouldnt that make it 460?

Answer 14

2x=920
x=460

Answer 15

right! :D

Answer 16

LOL i said that 20 minutes ago!!! thanks for all your help though!!!!!! greatly appreciated

Answer 17

that was one of those its so easy its hard ?s

Answer 18

ohhh...well the time thing of openstudy is buggy lol....deceived me haha wish they could fix it @_@ anyway glad to have helpedyou understand..it just takes experience haha