half a number plus 5 is 15 . what is the number ?
"let x be the number . always replace ` ` is ' ' with an equal sign ( 1 / 2 ) x + 5 = 15 ( 1 / 2 ) x = 15 - 5 ( 1 / 2 ) x = 10 x = 20 correct answer is b"
multiply(subtract(15, 5), const_2)