Question 380283
If Denny who walks 60 meters per minute has already walked 1800 meters,
 how many minutes will it take for John who cycles 210 per minute to catch
 up with Denny by bike?
:
Let t = no. of minutes for J to catch D
:
Find out how many minutes that D has walked already
{{{1800/60}}} = 30 minutes
:
When J catches D the will have traveled the same dist; 
Write a dist equation; dist = speed * time
:
J's dist = D's dist
210t = 60(t+30)
210t = 60t + 1800
210t - 60t = 1800
150t = 1800
t = {{{1800/150}}}
t = 12 minutes for J to catch D
;
:
Confirm this by finding the distance of each, should be equal:
210*12 = 2520 meters
60(12+30) = 2520 meters also