in the set of positive integers from 1 to 90 , what is the sum of all the odd multiples of 5 ?
"reduce 1 - 90 5 - 15 - 25 - 35 - 45 - - 55 - - 65 - - 75 - - 85 are valid multiples . add them - - > 405 d"
divide(multiply(90, multiply(const_3, 5)), 5)