Question

A man travelled at a speed of 20m/min for 100 min, and at a speed of 70m/min for 50 min. His average speed is

• A. 35 m/min
• B. $$\frac{70}{3}m/min$$
• C. 25 m/min
• D. $$\frac{110}{3} m/min$$

Answer 1

Answer:

$$\frac{110}{3} m/min$$

Speed S1 = 20 m/min

Time T1= 100min

S2=70 m/min

T2=50 min

Average speed = $\frac{20\times{100}+70\times{50}}{100+50}$

$=\frac{2000+3500}{150}$

$=\frac{5500}{150}$

$=\frac{110}{3} m/min$