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I like Math, I always have

I helped my brother with his Math homework tonight. He's in Grade 9.

An aircraft travels 5432 km from Montreal to Paris in 7 h and returns in 8 h. The wind speed is constant. Determine the wind speed and the speed in still air.

```                                   ---> wind
Let x = speed in still air    M ---------------------> P
y = wind speed               v = (x + y)
d = 5432 km                  t = 7h```
```     d                             ---> wind
v = --- , d = vt              M <--------------------- P
t                           v = (x - y) km/h
t = 8h```
```Since the distance from A to B is the same as the distance from
B to A, we have:```
```    7x + 7y = 5432
8x - 8y = 5432```
`Add the two lines to get:`
```    15x - y = 10864
15x = 10864 + y```
`Subtract the two lines to get:`
```   -x + 15y = 0
x = 15y```
`Plug in '15y' for 'x':`
```       225y = 10864 + y
224y = 10864
y = 48.5```
`Plug in 'y':`
```          x = 15(48.5)
x = 727.5```
Wind speed: 48.5 km/h
Speed of aircraft in still air: 727.5 km/h

Q.E.D.

Oct. 21st, 2001 07:20 pm (UTC)
Funny.
I could understand math if it was explained in a way I could understand it but no teacher ever wanted to take the time, merely re-stating what they had said in class.

I tend to reverse numbers with uncanny speed.

And I did stump my electronics instructor by asking if a problem could be solved another way, so much that he had to go home and try it out.

So there is a bit of savant in me, but I still get woozy looking at pages of numbers and tax forms terrify me.

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