Question

If a car covers 2/5^th of the total distance with v₁ speed and 3/5^th distance with v₂ then average speed is

• A. $\frac { 1 } { 2 } \sqrt { v _ { 1 } v _ { 2 } }$
• B. $\frac { v _ { 1 } + v _ { 2 } } { 2 }$
• C. $\frac { 2 v _ { 1 } v _ { 2 } } { v _ { 1 } + v _ { 2 } }$
• D. $\frac { 5 v _ { 1 } v _ { 2 } } { 3 v _ { 1 } + 2 v _ { 2 } }$

Answer 1

Answer: (D)

$\frac { 5 v _ { 1 } v _ { 2 } } { 3 v _ { 1 } + 2 v _ { 2 } }$

Answer 2

Average speed =$\frac { \text { Total distance travelled } } { \text { Total time taken } }$ $= \frac { x } { t _ { 1 } + t _ { 2 } }$

= $= \frac { 5 v _ { 1 } v _ { 2 } } { 2 v _ { 2 } + 3 v _ { 1 } }$