Question

Rachel and Monica are walking. Rachel is 10 steps ahead of monica. Rachel takes one step every second while Monica takes two steps every second. After how many seconds will Monica catch up with Rachel?

• A. 5
• B. 10
• C. 15
• D. 20

Answer 1

The correct option is B 10

Given that Rachel starts ahead of Monica by 10 steps and takes one step every second, the distance covered (d) in number of steps by Rachel in t seconds is
$d=10+t$
Monica takes 2 steps every second. The distance covered (d) by Monica in number of steps in t seconds is
$d=2t$

To find the time at which Monica catches up with Rachel, solve the 2 equations

Substituting for d in the first equation,
$2t=10+t$
$t=10$
Therefore, Monica will catch up with Rachel after 10 seconds.