In an examination,a student gets 5 marks for every right answer and loses 2 marks for every wrong answer.If he answers 50 questions and get 124 marks, how many are correct answers he attempted?
A teacher gave a student the task of adding āNā natural numbers starting from 1. After a while, the student reported his result as 700. The teacher replied that his result was wrong. The student realized that
he had added one number twice by mistake. Find the sum of the digits of the number which the student had added twice.
There are two groups A and B of a class, consisting of 42 and 28 students respectively . If the average weight of group B is 40 kg, find the average weight of the whole class.
A rich merchant had collected many gold coins. He did not want anybody to know about them. One day, his wife asked, "How many gold coins do we have?" After pausing a moment, he replied, "Well! If I divide the coins into two unequal numbers, then 37 times the difference between the two numbers equals the difference between the squares of the two numbers." The wife looked puzzled. Can you help the merchant's wife by finding out how many gold coins.