Answer:
the sidewalk speed q = 3km/hr
the tortoise speed p is 1.5 km/hr
Step-by-step explanation:
From the given information:
let the speed of the tortoise be p & the speed of the sidewalk be q
she's been running for 40 minutes (40/60 = 2/3) and that she's travelled 3 kilometres
Thus,
p + q =
p + q = 9/2
p + q = 4.5 ----- (1)
when returning, she travelled 3km in 2 hours
i.e. -p + q = 3/2
-p + q = 1.5 ----- (2)
Thus, by using the elimination method for equation (1) and (2)
p + q = 4.5 ----- (1)
<u>-p + q = 1.5 ----- (2) </u>
<u> 2q = 6 </u>
q = 6/2
q = 3 km/hr
From equation (1)
p + q = 4.5
p + 3 = 4.5
p = 4.5 - 3
p = 1.5 km/hr
Therefore, the sidewalk speed q = 3km/hr and the tortoise speed p is 1.5 km/hr