Answer: After 10 minutes
Step-by-step explanation:
Let Distance to be traveled be=D,
But you have a head start of 200 meters, therefor the distance you need to cover is reduced the expression becomes=D-200
Tom starts from the starting line so his distance=D
Since we need the time when Tom and you will meet, we equate the time Tom takes with his speed to the time you take with your speed to cover respective distances
Since Time=Distance/speed
Tom's time can be expressed as=D/420 equation 1
Your time can be expressed as=(D-200)/400 equation 2
Equating equation 1 and 2
(D/420)=(D-200)/400,solving
420(D-200)=(400)D
420D-84000=400D
420D-400D=84000
20D=84000
D=(84000/20)
D=42000
To get the time that they will meet, we substitute the value of D on either equation 1 or 2
(4200-200)/400=10 minutes