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2026 PEA Q25

Two countries HH and FF produce single goods with outputs YH,YFY_H, Y_F. Take HH's good as numeraire and pp as the relative price of FF's good. Consumers in country ii spend a fraction 1/41/4 of their expenditure on the foreign good. EiE_i denotes total expenditure of country ii measured in its own good. Given YH=120Y_H = 120, YF=100Y_F = 100, EH=80E_H = 80 and market clearing with YH+pYF=EH+pEFY_H + p Y_F = E_H + p E_F, find pp.

Reveal answer and solution

Answer

D

Solution

  1. 1

    By the Cobb--Douglas expenditure shares, each country spends 3/43/4 on its own good and 1/41/4 on the foreign good.

  2. 2

    Market clearing for HH's good (measured in units of HH's good).

  3. 3

    Demand by HH-consumers: 34EH=3480=60\tfrac{3}{4} E_H = \tfrac{3}{4}\cdot 80 = 60.

  4. 4

    Demand by FF-consumers: a fraction 1/41/4 of their total expenditure pEFp\,E_F

  5. 5

    expressed in HH-units, i.e.\ 14pEF\tfrac{1}{4}\,p\,E_F.

  6. 6

    Total demand equals supply YHY_H:

  7. 7
    60+14pEF  =  120pEF=240. 60 + \tfrac{1}{4}\,p\,E_F \;=\; 120 \quad\Longrightarrow\quad p\,E_F = 240.
  8. 8

    Budget identity. Total income == total expenditure (in the same units):

  9. 9
    YH+pYF  =  EH+pEF120+100p  =  80+240  =  320. Y_H + p\,Y_F \;=\; E_H + p\,E_F \quad\Longrightarrow\quad 120 + 100 p \;=\; 80 + 240 \;=\; 320.
  10. 10

    Thus 100p=200100 p = 200, hence p=2p = 2.

Answer structure / marking notes

Keeping the units straight (own good vs.\ numeraire) is the only delicate step.

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Content note

Imported from public/resources/isi/msqe/solutions/pea/2026/ISI_MSQE_PEA_2026_Solutions.tex. Question wording is retained from the available local TeX source; incomplete option blocks or ambiguous source status are flagged for review.