A person running an 800-meter race averages 130 meters per minute for the first 34 of the race. The average speed for the remainder of the race is 145 meters per minute. What is the person's average speed for the entire 800 meters rounded to the nearest whole number ?

প্রশ্নে বলা হচ্ছে, 800 মিটার একটি দৌড় প্রতিযোগিতায় এক ব্যক্তি $\frac{৩}{৪}$ অংশ পথ 130 মিটার/ মিনিট এবং পরবর্তী পথ 145 মিটার/ মিনিট বেগে গেলে মোট দৌড়ে তার গড় গতিবেগ কত ছিল?

Here, first part of race $= 800 \times \frac{3}{4}$= 600 meter

∴ Second part of race = 800 – 600 = 200 meter

Time taken to cross first part of race $\frac{600}{130}$ $\left[As, v = \frac{d}{t}\right]$

$=\frac{60}{13} meter/minute$

Again, Time taken to cross second part of race $= \frac{200}{145} = \frac{40}{29} meter/minute$

∴ Average speed $\frac{800}{{\displaystyle \frac{60}{13}}+{\displaystyle \frac{40}{29}}}= \frac{800}{4.615 + 1.379} = \frac{800}{5.994} = \frac{800}{6} [ nearest whole of 5.994 is 6]$

= 133.333 meter per minute

= 133 meter per minute (Approximately)