The equilibrium national income can be determined using the concept of the multiplier effect in economics. The multiplier effect refers to the increase in final income arising from any new injection of spending.

The size of the multiplier depends upon the marginal propensity to consume (MPC). The formula for the multiplier (k) is:

\(k = \frac{1}{1 - MPC}\)

Given that the MPC is 0.7, we can calculate the multiplier as follows:

\(k = \frac{1}{1 - 0.7} = 3.33\)

The change in income (ΔY) is then calculated by multiplying the change in government spending (ΔG) by the multiplier (k):

\(ΔY = k * ΔG\)

Given that government expenditure increased by N 150 million:

\(ΔY = 3.33 * N 150 \text{million} = N 500 \text{million}\)

Therefore, the equilibrium national income will increase by N 500 million.