Which system of equations has no solution?

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

Apark is in the shape of a rectangle. the park authorities are planning to build a 2-meter-wide jogging path in the park (shown as the shaded region in the image). what is the area of the jogging path? plz

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.