GMATD11 wrote:

91)By what % did the median household income in country Y decrease from 1970 to 1980?

a) In 1970 the median household income in Country Y was 2/3 of the median household income in Country X

b) In 1980 the median household income in Country Y was 1/2 of the median household income in Country X

Let median household income in Country Y is y

Let median household income in Country X is x

a) in 1970 y=2/3x

not sufficient

b) in 1980 \(\color{red}{y=1/2x}\)

not sufficient

"x" may not be median household income for country x in 1980. It could be (x+100) or (x-89) or (x*4.5)

Let's take some numbers;

1970:

Median income for x: 90

Median income for y = (2/3)*90 = 60

1980

Median income for x: 120

Median income for y = (1/2)*120 = 60

Percent decrease: 0%

case II:

1970:

Median income for x: 90

Median income for y = (2/3)*90 = 60

1980

Median income for x: 30

Median income for y = (1/2)*30 = 15

% decrease for y = 45/60*100 = 75%

Ans :"E"

_________________

~fluke

GMAT Club Premium Membership - big benefits and savings