what is the average ( arithmetic mean ) of all the multiples of 10 from 10 to 160 inclusive ?
10 and 190 inclusive would mean there are 15 terms . no need to add up all the terms and further divide by 15 since the terms are evenly spaced in ascending order from 10 , 20 , 30 . . . . . . . . 160 the middle term is the average which is the tenth term = 70 c is the answer .
divide(subtract(160, multiply(10, const_2)), const_2)