Math problem help because I'm an idiot (1 Viewer)

[belljr]

You make X.   Every year you receive a flat increase of Y.

How many years until you reach Z .

So for example.

X = 100000

Y = 3%

Z = 125000

How many years until you reach Z?

Obviously the brute force way is 

Year 1: 103000

Year 2: 106090

Year 3: 109272.70

Year 4: 112550.88

etc etc....   

I can'tfor the life of me remember how to do this...

 

[Dinsy Ejotuz]

100,000*(1.03^x) = 125,000

1.03^x = 125,000/100,000

1.03^x = 1.25

x * ln(1.03) = ln(1.25)

x = ln(1.25)/ln(1.03)

x = 7.55

 

[jhib]

z=x(1+y)^t

with y being the rate as a decimal (3% = 0.03) and t being the number of years

t= ln(z/x)/ln(1+y)

 

[Van Dyman]

The answers above seriously hurt my head. I've forgotten so much high school math, and my kid will be needing help with stuff just like that very soon.

 

[bostonfred]

https://bfy.tw/PR76

 

[Cold Dead Hands]

The large pizza is the better deal.

 

[Lomez]

You make X.   Every year you receive a flat increase of Y.

How many years until you reach Z .

So for example.

X = 100000

Y = 3%

Z = 125000

How many years until you reach Z?

Obviously the brute force way is 

Year 1: 103000

Year 2: 106090

Year 3: 109272.70

Year 4: 112550.88

etc etc....   

I can'tfor the life of me remember how to do this...

Maybe math just isn't your thing.

I know. Let's have a face contest.

 

[top dog]

The large pizza is the better deal.

But how many pieces are in the pizza????

 

[Leroy Hoard]

But how many pieces are in the pizza????

When confronted with questions such as this,  I always refer to the wisdom of Yogi Berra:

"You better cut the pizza in four pieces,  because I'm not hungry enough to eat six."