"HOW FAR IS LEFT TO TRAVEL" MENSA BRAIN-TEASER PUZZLE. EASY LEARN FRACTIONS

[@Wyld1one]

The solution isn't exactly precise either. The distance she travels is actually d = (2,000 / 27) - 10, it's not precise because you get an infant repeating series after that. My work: 2.5 1.4 2.5 1.2 S (amt traveled + amount left, remainder left = (n) 2/5s + 3/5s = 5s, r1=3/5s 1/4r1+ 3/4r1 = r1, r2=3/4r1 2/5r2 + 3/5r2 = r2 , r3=3/5r2 1/2r3 +1/2r3 = r3, r4 = 1/2r3 (destination reached) r4 = 10, told this r3 =20 , r2=5/3r3, r1 = 4/3r2 , s= 5/3r1 r2 = 100/3 r3 r1 = 400/9 s S = 2000/27 So the distance biker traveled was actually (2000/27) -10, which is exact since computing it will give you a repeating decimal infinitely

[@Wyld1one]

Sorry if I didn't make this quite clear after the line of r4 = 10 What I'm doing is I'm reverse substituting - unless I'm working backwards back up the calculation tree. Once you get the final version of s, you can verify by working back down the calculations in order