How does this important money-vending machine work? How does the bank decide how much money is put in it? A curious Ramya gets answers for many such questions from her father
It was a pleasant February morning. Amma had taken Rishabh for a dentist’s appointment. Ramya and Appa were walking towards the market to do some vegetable and grocery shopping. On the way, Appa wanted to stop at the ATM to withdraw cash.
However, the ATM shutters were down half-way and there were a couple of men in safari suits wielding guns, guarding the door. The watchman told Appa that the ATM was getting re?lled and that it eould take another 15 minutes to be ready for use. Appa nodded and told Ramya, “Let’s go ?nish our shopping and stop by on the way back home at the ATM.” Ramya quietly followed Appa, after a last glance at the men with the guns.
After a few steps Ramya sighed and said, “That was scary Appa, the guns and all...” Appa smiled and said, “Don’t be scared Ramya. They were just guarding the vehicle and the team who were re?lling the ATM since there was a lot of money there.”
Of course, Ramya had questions. “Appa, I know the bank re?lls the ATM. But how do they know how much money to put in? Also, how do they know whose money to put in there as so many people come to take their money from the ATM?”
“Whoa, slow down Ramya, let us talk about this in detail once we get back home.” So, they ?nished the shopping quickly, checked if the list they had put together was ticked o? completely,went to the ATM and then walked back home. The minute they entered the door, Ramya said, “Appa, we are back home, tell me now!” Appa laughed and said, “Yes, of course, Ramya, I have not forgotten! I am impressed that you know who re?lls the ATM.” Ramya looked very happy. Appa continued, “Now, when Amma and I put together the list of vegetables and groceries to buy, we estimated the quantity we need for the week based on how much all four of us usually eat.
Similarly, the bank estimates the amount to be re?lled, depending upon how much money people have withdrawn from this particular ATM in the past. Every time someone withdraws money in the ATM, the computer records the account number, time and date and amount.” “Oh!” said Ramya with her eyes wide open. “There is so much going on behind the ATM! But Appa, what if someone else takes our money out of the ATM and we don’t get any?” Appa said, “Do you remember, when I withdrew money from the ATM, I had to use my card and punch in a secret number (PIN)? That is how the ATM allows me to withdraw money from my account and not any other person’s account.”
Appa smiled and drew a diagram to help Ramya understand better ( see image ). After hearing all this, Ramya said, “The ATM looks useful, but I like the vending machine at the airport, as it gives out chocolates and snacks instead of money!” Appa quipped, “But the ATM provides the money for that vending machine, Ramya!” Laughing, they went to put away the groceries and vegetables before Amma and Rishabh came back.