Carcass wrote:
Which one of the following choices does not equal any of the other choices?
(A) 5.43 + 4.63 – 3.24 – 2.32
(B) 5.53 + 4.73 – 3.34 – 2.42
(C) 5.53 + 4.53 – 3.34 – 2.22
(D) 5.43 + 4.73 – 3.24 – 2.42
(E) 5.43 + 4.73 – 3.14 – 2.22
Here's one approach:
First, ignore the decimals to get:
(A) 543 + 463 – 324 – 232
(B) 553 + 473 – 334 – 242
(C) 553 + 453 – 334 – 222
(D) 543 + 473 – 324 – 242
(E) 543 + 473 – 314 – 222
Subtract 543 from all expressions to get:
(A) 0 + 463 – 324 – 232
(B) 10 + 473 – 334 – 242
(C) 10 + 453 – 334 – 222
(D) 0 + 473 – 324 – 242
(E) 0 + 473 – 314 – 222
Subtract 453 from all expressions to get:
(A) 0 + 10 – 324 – 232
(B) 10 + 20 – 334 – 242
(C) 10 + 0 – 334 – 222
(D) 0 + 20 – 324 – 242
(E) 0 + 20 – 314 – 222
Add 334 to all expressions to get:
(A) 0 + 10 + 10 – 232
(B) 10 + 20 + 0 – 242
(C) 10 + 0 + 0 – 222
(D) 0 + 20 + 10 – 242
(E) 0 + 20 + 20 – 222
Add 242 to all expressions to get:
(A) 0 + 10 + 10 + 10
(B) 10 + 20 + 0 + 0
(C) 10 + 0 + 0 + 20
(D) 0 + 20 + 10 + 0
(E) 0 + 20 + 20 + 20
At this point, we can see that the correct answer is E
ASIDE: The above calculations could be performed in one step (to speed things up)
Cheers,
Brent