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5 votes
63,360, 63,366, 63,372, 63,378, 63,384, ... What is Barry's altitude above sea level, in inches, when he is standing on the 65th step above the one-mile step (counting the one-mile step itself as step #1)?

User Auhmaan
by
5.7k points

1 Answer

4 votes
You need to convert the sequence to a formula

Since step 1 is 63,360 and each is 6 higher.

First I will try...

Altitude = 63,360 + 6x

Lets check it with step 1 ...

= 63,360 + 6(1)
= 63,366
wrong.

6 too high

So the formula would be

Altitude = 6x + 63,354

Lets test for known step 5 which the sequence says will be 63,384 ...

= 6(5) + 63,354
= 30 + 63,354
= 63,384

Looks good !

Now...

For step 55 just plug in 55 as X to solve.

= 6(55) + 63,354

then simplify
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User Jakadinho
by
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