A. There are 6 different ways to place an order:-
All tricycles . There were 5*33 = 15 wheels.
All wagons. 5 * 4 = 20 wheels
2 Tricycles, 3 wagons. 18 wheels (2*3 + 3 *4 = 18)
3 Tricycles, 2 wagons. 17 wheels ( 3*3 + 2*4 = 17)
1 tricycles, 4 wagons. 19 wheels
4 tricycles, 1 wagon 16 wheels.
B.
2 wagons were ordered if there ere 17 wheels ( see Part A).