Physics - Kinematics Question with Solution | TestHub

${\text{V}}_{\text{av}}=\frac{\text{distance travelled}}{\text{time taken}}$

$\Rightarrow {\text{V}}_{\text{av}}=\frac{\text{AB}+\text{BC}}{\frac{\text{AB}}{40}+\frac{\text{BC}}{60}}$

${\Rightarrow \text{V}}_{\text{av}}=\frac{\text{6BC}+\text{BC}}{\frac{\text{6BC}}{40}+\frac{\text{BC}}{60}}$

${\text{V}}_{\text{av}}=\frac{7\times 240}{36+4}\Rightarrow {\text{V}}_{\text{av}}=\frac{7\times 240}{40}$

$\Rightarrow {\text{V}}_{\text{av}}=42\text{km/h}$