CareerCup

suppose the initial height of the tree is a variable named "start"

start*2^9=40
start*2^(n-1)=5

divide two equations, then 8=2^(10-n)

n=7

7th. because 10th->40, 5->40, 8 times->3 days back.
Is this skill test, or just a brain teaser?

thats what she said

x: initial height
d: # days

let initial height = h

1st day height = h;
2nd day height = 2h;
.
.
10th day height = 2^9 h;

given height on day 10 = 40
so,

2^9 h = 40 => h = 40 / 2^9;

we can write 40 = 2 x 2 x 2 x 5 = 2^3 x 5

so h = 2^3 x 5 / 2 ^9
h = 5 / 2^6

cross multiply both sides by 2^6
we get ,

2^6 h = 5 . Therefore, on 7th day height is 5 feet

10th day 40...then 9th day 20...8th day 10...7th day is 5

seeds seem to have height in negative in the start :P
magic seeds!

seed with fractional height ...

7 th day

7th day..easy one

Lol, the seed has height = 0???