A person who has a certain amount with him goes to market. He can buy 50 oranges or 40 mangoes. He retains 10% of the amount for taxi fares and buys 20 mangoes and of the balance he purchases oranges. Number of oranges he can purchase is
Choose the correct choice:  A) 36  B) 40  C) 15  D) 20  E) 10
Explanation :   Let the person has x Rs , then price of 50 oranges or 40 mangoes is x Rs.   Therefore, from given information x = (x / 10) + (x / 2) + Amount left.   Hence, the amount left to buy oranges is (2x / 5) , since price of 50 oranges or 40 mangoes is x Rs , hence price of 1 orange, 1 mango is (x / 50), (x / 40) respectively.   Hence, he can buy (2 /5) x 50 = 20 oranges.   Answer : 20
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A person who has a certain amount with him goes to market. He can buy 50 oranges or 40 mangoes. He retains 10% of the amount for taxi fares and buys 20 mangoes and of the balance he purchases oranges. Number of oranges he can purchase is