help 1

[lean dust]

Answer is 8 years

[woven tusk]

help 1

[leaden saffron]

If you call the initial value x

What will the values after a year be?

[scarlet trellis]

1x?

1 + x?

wait this is easy

[lean dust]

91 percent ?

[scarlet trellis]

53/9?

[leaden saffron]

Exactly

[scarlet trellis]

100-9

[lean dust]

Do I keep minusing 9 percent till I get 47 percent

[leaden saffron]

So it will be 0,91x

Now what will it be after 2 years

Not exactly

[scarlet trellis]

no

[leaden saffron]

You keep multiplying by 0,91

Because each year it is 0,91 times the value of the year before

[lean dust]

What do multiply by 0.91

[scarlet trellis]

yes

deprictiation formula

p(1-r/100)^n

[leaden saffron]

Lets call the value after n years a_n. Then the value after n+1 years is 0,91a_n

[lean dust]

Yea

[leaden saffron]

The vapue of the year before

[lean dust]

100 times 0.91?

[leaden saffron]

So you have to solve 0,91^x=0,47

[lean dust]

What’s x

[leaden saffron]

The ammount of years

[lean dust]

How do I find the years

[leaden saffron]

By solving this

Just type 100 in your calculator and keep multiplying by 0,91 until you reach 47

Then how many times did you mutiply

[lean dust]

Ok 1 sec

[scarlet trellis]

hold on, if you subtrarct 1 year, then for the second year isnt it 9 perecent of 91?

[leaden saffron]

Yes

[scarlet trellis]

thats 82.81

[leaden saffron]

So you just multiply by 0,91 each time

[scarlet trellis]

then 9% of that

right

[leaden saffron]

Yes exactly that

Until you reach 47

[scarlet trellis]

but the final answer will end up in a decimal

[lean dust]

Yes I got it

Thanks

[leaden saffron]

Yes you can just round it I think

[scarlet trellis]

then alright