Answer:
Malory will catch up with Dori in 25 minutes.
Step-by-step explanation:
Given:-
Dori walking at 50 steps/min.
Malory walking at 90 steps/min.
Now, as Dori left the house 20 mins ahead of Malory and
Dori is walking at speed of 50 steps/min, that means
Dori is walking ahead of Malory by 50 (steps) [tex]\times[/tex] 20 (minutes)
Dori is walking ahead of Malory by 50[tex]\times[/tex] 20
Dori is walking ahead of Malory by = 1000 steps
Now, let time be t of walking by Dori and Malory,
to calculate the time for Malory to catch up with Dori can be written as,
[tex](50\times t)+1000=90\times t[/tex]
where, 1000 is the headstart for Dori, 50 and 90 is the walking speed of Dori and Malory respectively in steps/ min.
[tex]90t-50t=1000[/tex]
[tex]40t=1000[/tex]
[tex]t=\frac{1000}{40}[/tex]
[tex]t=25\ minutes[/tex]
Therefore Malory will catch up with Dori in 25 minutes.
