We drove our Car in rural Konkan area recently. Distance was about 160 miles. Roads were good and bad in patches. On good patches, we enjoyed driving at speed of 60 miles per hour. Whereas, on bad patches, it was difficult to go beyond 10 miles per hour. A general feeling was that we were at the slower speed for about 4 hours and at the higher speed for only 2 hours. Roads were bad; that was the conclusion. You can understand that about two-third of the travel time, we were struggling to get a speed of 10 miles per hour. Let us see another aspect of the journey by getting idea about length of the bad or good road. Since, we had 4 hours of drive at a speed of 10 miles per hour, the length of such roads was 10*4 = 40 miles. Similarly, length of the road travelled in 2 hours at 60 miles per hour can be computed as 60*2 = 120 miles. So, total distance travelled was 120+40 = 160 miles, out of which 120 miles were good and only 40 miles were rough. In terms of %, only (40/160)*100 = 25
I purchased 7 mangoes from a nearby fruit seller yesterday as there were that many persons in my home. There are plenty of fruit sellers around, so there is no reason of purchasing more and storing. The fruit seller was a lady in her seventies and probably had no formal education. She sold those mangoes at ₹140/kg. She weighed the mangoes selected by me. It was 1 kg 750 gm. She asked me to pay ₹245 while transferring the mangoes into my bag. I was surprised as the time taken by her to do this calculation was practically nothing and she didn’t use calculator or pen-paper. I took more time than her to do this calculation manually and found the amount to be right. I thought, she might have got another customer earlier purchasing same quantity of mangoes, so she might just remember the amount! But, it was not so. I was curious to know her process of doing the calculation. She said; 14*7 = 98 for 700 gm, +₹7 for 50 gm = ₹105 for 750 gm. Add 140 for 1 kg. So, 140+105=₹245. W