Martin bought a sofa with 1/3 of his money. He also bought a table and

6 chairs. Each chair cost $60. The cost of the table was $90 more than the
total cost of the chairs. He then used 2/5 of his remaining money to buy a
washing machine. He had 1/7 of his money left. How much money did Martin have at first?

amount of money that Martin has ---- x

cost of sofa --- (1/3)x
cost of 6 chairs = 360
cost of table = 450
amount of money he has left at that point
= x - (1/3)x - 360 - 450
= (2/3)x - 810

after he spent 2/5 of the above on washing machine, he has 1/7 of x left
(3/5)((2/3)x - 810) = x/7
(2/5)x - 486 = x/7
multiply by 35
14x - 17010 = 5x
9x = 17010
x = 1890

check:
cost of sofa, chairs and table = (1/3)(1890) + 360 + 450 = 1440
leaving him with 450
spends 2/5 of 450 or 180 on washing machine, leaving him with
450-180 or 270
which just happens to be 1/7 of 1890
Yeahhh!