एक धनात्मक संख्या और उसके तीन-पांचवें (three-fifth) भाग का अंतर 50 है। वह संख्या क्या है?

Some friends decided to go on a picnic and the amount fixed for expenditure was ₹ 768. Due to the non-arrival of four friends, each participating friend had to bear an additional amount of ₹ 16. How many friends participated in the picnic?

From a certain number of apples, a man sells half the number of apples plus 1 to the first customer, sells 13 of the remaining apples plus 1 to the second customer, and 15 of the remaining apples plus 1 to the third customer. He then finds that he has 3 apples left. How many apples did he have initially?