Three shirts cost 3 * 5 = $<<3*5=15>>15.
Two pairs of jeans would cost 2 * 10 = $<<2*10=20>>20.
Four hats would in total cost 4 * 4 = $<<4*4=16>>16.
So for three shirts, two pairs of jeans, and four hats, you would need to pay 15 + 20 + 16 = $<<15+20+16=51>>51.
#### 51