There are two articles A and B in a certain store and if you buy four pieces of A and three pieces of B, it is 1000 yen.
Moreover, the price of three A is 70 yen higher than the price of two B.
Find a price of one piece of A.
Answer
130 yen
Solution
4A + 3B = 1000,
8A + 6B = 2000
3A = 2B + 70,
2B = 3A - 70,
6B = 9A - 210
8A + 9A -210 = 2000
17A - 210 = 2000
17A = 2210
A = 130 yen
