The ratio 4:2 simplifies to 2:1 after you divide both parts by 2
The ratio 2:1 means you have twice as much shirts compared to pants
x = number of shirts
y = 2*x = number of pants
At this point is where we get stuck. We don't know the price for one shirt, nor the price for one pair of pants, so we don't know how many of each we can buy. Please double check your book to make sure you have typed everything about the problem.