This is a problem involving two unknown variables in which can be broken down to one variable.
Let j = the number of jeans were bought
and s = 2*j = the number of shirts bought
Now set up an equation stating the total amount of dollars spent buying jeans and shirts in which is:
45*j + 25*s = 190
Substitute s = 2*j in the equation.
45*j + 25*(2*j) = 45*j + 50*j = 95*j = 190
Now divide both sides of the equation by 95 in which give j = 2 and s = 2*2 = 4
Hence, 2 jeans and 4 shirts were bought. The way to check the answer is to substitute the answers but into the original equation.
45*2 + 25*4 = 90 + 100 = 190. Therefore, the answers check to be correct.