The equilibrium quantity is the value of p when the demand d and supply s is equal. Therefore we equate the two equations:
60 – 10p + 2y = 20p – 20pm
We are given that:
y = 70
pm = 5
p =?
60 – 10p + 2(70) = 20p – 20(5)
200 – 30p = - 100
- 30p = - 300
p = 10