You went to the store and purchased a pair of sneakers, socks and a shirt. The shirt cost 40% of the cost of the sneakers. The socks cost 20% of the shirt. How much is each item if the total amount spent is $118.40?
Here you have sneakers (x), socks (y) and shirt (z). Each of these can be expressed as a function of the sneakers. For example the shirt (z) is 0.4 times the price (40%) of the sneakers, and so on. Then we have the following:
If y is 0.2z then y can also be writen as 0.2*0.4x=0.08x
Sneakers cost 80, shirt costs 32 and the socks costs 6.4