What’s the answer? and this is social studies

The “rule of 72” is used to approximate the time required for prices to double due to inflation. if the inflation rate is r%, then the rule of 72 estimates that prices will double in 72/r years. for instance, at an inflation rate of 6%, prices double in about 72/6 or 12 years. write a program to test the accuracy of this rule. for each interest rate from 1% to 20%, the program should display the rounded value of 72/r and the actual number of years required for prices to double at an r% inflation rate. (assume prices increase at the end of each year.)

Write a program that inserts the digits of an integer into an array in originalorderfollowed by reverse order. first, promptthe user to enter a positive integer(> 0). determine the number of digits of the integer. create a dynamically allocated integer arrayof a size twice the number of digits.now insert the digits in original order which will occupy half of the array. then, insert the digits in reverse order.finally, output thedigits in thearray.use at least two functions to organize your program.

What are "open-loop" and "closed-loop" systems