jackchung asked in 社會與文化語言 · 1 decade ago

GMAT-data sufficiency (數學-3)

Of the 75 houses in a certain community, 48 have a patio. How many of the

houses in the community have a swimming pool?

(1) 38 of the houses in the community have a patio but do not have a swimming

pool.

(2) The number of houses in the community that have a patio and a swimming pool

is equal to the number of houses in the community that have neither a

swimming pool nor a patio.

答案B

1 Answer

Rating
  • Thomas
    Lv 6
    1 decade ago
    Best Answer

    A: 有patio; 無pool

    B: 無patio; 有pool

    X: 有patio; 有pool

    Y: 無patio; 無pool

    A+X: 有patio

    B+X: 有pool

    所以問題:

    A+X = 48

    A+X+B+Y = 75

    ========

    (2)

    X=Y

    =>

    A+X+B+Y=(A+X) + (B+X) = 75

    因為 A+X =48

    所以 B+X = 75-48=27

    可以得知, 有 pool 有 27戶

    2008-03-27 16:51:38 補充:

    至於 (1)

    由於只得知

    A=38

    X=10

    B+Y=75-48=27

    B=0 or 1 or 2 or .....27

    所以,

    B+X = 10,11,12,......,37 都有可能

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