Ermek bought 4 books. except for the first book, other books there are 420 tenges, and except for the 2nd the book, the sum of books is 400 tenges, and except for the 3rd the book, the sum is 380 tenges and if not to consider the 4th book, the sum is 360 tenges. it is necessary to find the price everyone books

102
420-400=20 400-20=380 380-360=201) 420 - 400=20 (ten) 2) 400-20=380 (ten) 3) 380-360=20 (ten) Answer: 20 tenges are costed by one book
268
Answer add