Question

Andrew and Daniel recently took part in a marathon. After they had finished, they noticed
that Andrew finished ahead of twice as many runners as finished ahead of Daniel, and that Daniel finished ahead of 1.5 times as many runners as finished ahead of Andrew. Andrew finished in 21st
place. How many runners took part in the marathon?

Answer 1

20 ahead of andrew
30 behind daniel

Now we know that

30+1+x = 2x+1+20
10=x

So, there were 41 runners, in order:

30...Daniel...10
20...Andrew...20

Answer 2

or, better,

20..Andrew..9..Daniel..10

Answer 3

A = 1 + 2x
Runners that finished ahead of Daniel is x
21 = 1 + 2x
21 - x = 2x
X = 10

Runners that finished ahead of Andrew is 20
D = 1.5 x 20
= 30 + 1
= 31
Total = 31 + 10
= 41

Answer 4

Let the many runners that finished ahead of Daniel be x
Andrew=1+2x
21=1+2x
21-1=2x
20=2x
x=10
Many runners ahead of Andrew are 20
Daniel =1+1.5×20
=1+30=31
Total = 31+10=
41