Rocky spent 1/5 of his money on 8 pencils and 2 markers. The cost of each markers is twice the cost of each pencil. He bought some more markers with 5/8 of his remaining money. How many markers did Rocky buy altogether?
cost of 1 pencil --- x
cost of 1 marker = 2x
amount of money at beginning ---- m
8x + 2(2x) = (1/5)m
12x = 1/5 m
m = 60x
spent more on 5/8 of 60x = 75/2 x
but each marker cost 2x
so number of extra markers = (75x/2) / (2x)
= 75/4 = 18.75
he could only buy 18 more, or else it would be more than 5/8 of the remaining money.
So, including the initial 2 markers he bought a total of 20 markers