in an entrance exam , 3 marks is awarded for every correct answer and ( - 1 ) for every wrong answer . if a student gets 38 marks after attempting all questions , find the number of questions answered correctly if the total questions were 70 .
explanation : let x be the number of questions answered correctly . hence , number of questions whose answer were wrong = ( 70 – x ) 3 * x + ( 70 – x ) * ( - 1 ) = 38 4 x = 38 + 70 = 108 x = 27 answer c
subtract(70, divide(subtract(multiply(3, 70), 38), add(3, 1)))