850 - ( 1500 ÷ ? ) × 8 / 15 = 770
"explanation : = > 850 - ( 1500 ÷ ? ) × 8 / 15 = 770 = > 850 - 770 = ( 1500 ÷ ? ) × 8 / 15 = > 80 = ( 1500 ÷ ? ) × 8 / 15 = > 80 × 15 / 8 = ( 1500 ÷ ? ) = 150 = > 1 / ? = 150 / 1500 = 1 / 10 = > ? = 10 answer : option b"
subtract(850, divide(1500, 8))