given x beats y by 10 m.

y beats z by 10 m.

suppose when y at 1m then x shld b at 11.

and when x at 1 y at 11.

now x:y 11:1 and y:z 11:1

now x:y:z 22:11:1

nowx:z 22:1 i.e x beats z by 21m.

Hi

Here X beats Y by 10m & Y beats Z by 10m

Now

hey think logically

if y reach 100m then z will be at 90m

so if y reach 90m then z will be at 91m.

they given when x reach 100m y will be at 90m

but we found that when y @ 90m z @81 m

so the ans is 100-81 19m

this is the right ans.

Obviously 20 m.

Let the speed of X is 10m/s then A will Complete the race in 10 Secs.

Now X beat Y by 10m so Y was at 90m mark when X completed the race i.e

Y covered 90 m in 10 secs so speed of Y is 9m/s. So now Y will take additional

10(m) / 9(m/s) secs i.e 1.11 secs to complete the race.

Y beat Z by 10 m so Z covered 90 m in 10 + 1.11 secs

speed of Z is 90/11.11 8.1m/s now he will also take additional 10/8.1 secs

i.e. 1.234 sec to cover next 10 m.

Now Z will reach 100 m 1.11 + 1.234 2. sec after X

Thats why X beat Z by 10 * 2.344 23.44 m

answer is 020 metres