Use the fact that 1 axe head = 3.20 trade value.
Let N denote number of axe heads needed to trade for a trade gun.
3.20×N=120.00
》 N=120/3.2 which will give number of axe heads needed. Round to the nearest ones place if you must.
He is at 70 feet above sea level. -30+100 is 70.
-3=2x+10= -13=2x = -0.153