A person walks along a straight road from his house to a market 2.5kms away with a speed of 5 km/hr and instantly turns back and reaches his house with a speed of 7.5 kms/hr. The average speed of the person during the time interval 0 to 50 minutes is (in m/sec)

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

$4 \frac{2}{3}$

$\frac{5}{3}$

$\frac{5}{6}$

$\frac{1}{3}$

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Time required to reach market = 30 min = 1/2 hr
remaining time = 50 – 30 = 20 min
distance in next 20 min = $7.5 \times \frac{20}{60} = 2.5 km$
$\begin{array}{l} ∴ v_{avg} = \frac{2 v_{1} v_{2}}{v_{1} + v_{2}} = \frac{2 \times 5 \times 7.5}{5 + 7.5} = 6 km / hr \\ v_{avg} = 6 \times \frac{5}{18} m / s = \frac{5}{3} m / s \end{array}$

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET