Question

Samir begins riding his bike at a rate of 6 mph. Twelve minutes later, Chris leaves from the same point and bikes along the same route at 9 mph. At any given time, t, the distance traveled can be calculated using the formula d = rt, where d represents distance and r represents rate. How long after Chris begins riding does he catch up to Samir? 4 min 12 min 24 min 40 min

Answer 1

Answer:

The correct answer option is 24 min.

Step-by-step explanation:

Let  us assume t to be Chris's time (in hours)  so we can write the following equation:

Samir's time (in hours)  $=t + \frac{12}{60} = t + 0.2$

Chris's rate  $(r_1)=9 mph$

Samir's rate  $(r_2)=6 mph$

Then putting the values in the formula to get:

$r_1t = r_2(t + 0.2)$

$9t = 6(t + 0.2)$

$9t=6(t+0.2)\\\\9t=6t+1.2\\\\9t-6t=1.2\\\\3t=1.2\\\\t=0.4$

t = 0.4 which will be $0.4*60=24$

Therefore, Chris catches up Samir after riding for 24 minutes.