(a)

(i)

C = 200 + 0.75(5000 - 1050) = 200 + 0.75 x 3950 = 200 + 2962.5 = 3162.5

National saving = (Y - C) + (T - G) = (5000 - 3162.5) + (1050 - 1200) = 1687.5

(ii)

I = 1500 - 60 x 3 = 1500 - 180 = 1320

(iii)

Tradde balance (NX) = Y - C - I - G = 5000 - 3162.5 - 1320 - 1200 = - 682.5

(iv)

NX = 450 - 200e

- 682.5 = 450 - 200e

200e = 1132.5

e = 5.6625

(b)

C = 200 + 0.75(5000 - 1050) = 200 + 0.75 x 3950 = 200 + 2962.5 = 3162.5

National saving = (Y - C) + (T - G) = (5000 - 3162.5) + (1050 - 1000) = 1887.5 (National saving increases by 200)

(ii)

I = 1500 - 60 x 3 = 1500 - 180 = 1320 (Investment stays the same)

(iii)

Trade balance (NX) = Y - C - I - G = 5000 - 3162.5 - 1320 - 1000 = - 482.5 (Trade balance increases by 200)

(iv)

NX = 450 - 200e

- 482.5 = 450 - 200e

200e = 932.5

e = 4.6625 (Exchange rate decreases by 1)

Decrease in government spending will increase national savings. The savings curve shifts righttward, decreasing interest rate and increasing equilibrium saving and investment.

As interest rate decreases, net capital outflow increases, which increases net exports (trade balance) and decreases exchange rate.

In following graph, panel A shows saving (S) and investment (I) curves. S0 and I0 are initial national saving and investment curves intersecting at point A with initial interest rate r0 and initial savings & investment Q0.

As savings increase, S0 shifts right to S1, intersecting I0 at point B with lower interest rate r1 and higher quantity of saving and investment Q1.

In panel B (showing net capital outflow as inverse function of interest rate), lower interest rate from r0 to r1 increases net capital outflow from NCO0 to NC01.

In panel C (showing net exports as inverse function of exchange rate), an increase in net capital outflow from NCO0 to NCO1 increases net exports from NX0 to NX1 and dencreases exchange rate from e0 to e1.

(c)

(i)

C = 200 + 0.75(5000 - 1050) = 200 + 0.75 x 3950 = 200 + 2962.5 = 3162.5

National saving = (Y - C) + (T - G) = (5000 - 3162.5) + (1050 - 1200) = 1687.5 (National saving stays the same)

(ii)

I = 1500 - 60 x 5 = 1500 - 300 = 1200 (Investment decreases by 120)

(iii)

Trade balance (NX) = Y - C - I - G = 5000 - 3162.5 - 1200 - 1200 = - 562.5 (Trade balance increases by 120)

(iv)

NX = 450 - 200e

- 562.5 = 450 - 200e

200e = 1012.5

e = 5.0625 (Exchange rate decreases by 0.6)

Decrease in investment will shift the investment curve leftward, decreasing interest rate and decreasing equilibrium saving and investment.

As interest rate decreases, net capital outflow increases, which increases net exports (trade balance) and decreases exchange rate.

In following graph, panel A shows saving (S) and investment (I) curves. S0 and I0 are initial national saving and investment curves intersecting at point A with initial interest rate r0 and initial savings & investment Q0.

As investment decreases, I0 shifts left to S1, intersecting I0 at point B with lower interest rate r1 and lower quantity of saving and investment Q1.

In panel B (showing net capital outflow as inverse function of interest rate), lower interest rate from r0 to r1 increases net capital outflow from NCO0 to NC01.

In panel C (showing net exports as inverse function of exchange rate), an increase in net capital outflow from NCO0 to NCO1 increases net exports from NX0 to NX1 and dencreases exchange rate from e0 to e1.