in an examination , 20 % of total students failed in hindi , 70 % failed in english and 10 % in both . the percentage of these who passed in both the subjects is :
"pass percentage = 100 - ( 20 + 70 - 10 ) = 100 - 80 = 20 answer : b"
subtract(const_100, subtract(add(20, 70), 10))