Problem
You decide to start saving up so you can buy a vintage car for $100,000. The seller promises that they will wait as long as it takes you to pay the $100,000 sticker price, which won't change. Right now you can put aside $23,000. If you can invest at 16% p.a., how many years (rounded to the 1st decimal place) must you wait, assuming you won't add to the investment other than letting the interest's compound?