answer to question paper 1------- IPM STD 5

In a test there are 50 questions. A student gets 5 marks for the right answer and 1 mark is deducted for every wrong answer. If she attempted all the questions and got 78% marks, how many questions did she attempt correctly?

Answer:

Let the number of correct questions be y

So, the number of wrong questions = (50 – y)

Therefore, marks obtained by the student = 5y + (50 – y) = 4y + 50

Given that she secured 78% marks. 

Therefore, 4y + 50 = 78

Or y =  28/4 = 7.

So, correct answer = 50 – 7 = 43.