Percentages !!`

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vishubn: Legendary Member; Posts: 574; Joined: Sun Jun 01, 2008 8:48 am; Location: Bangalore; Thanked: 28 times

Percentages !!`

by vishubn » Sun Dec 14, 2008 1:19 am

If Jack’s and Kate’s annual salaried in 1985 were each 10 percent higher than their respective annual salaries in 1984, what was Jack’s annual salary in 1984?
(1) The sum of Jack’s and Kate’s annual salaries in 1984 was $50,000.
(2) The sum of Jack’s and Kate’s annual salaries in 1985 was $55,000.

My appp

A) j + k=50000

Insuff

B) 1.1j+1.1k=55000

together

Possible!! But Oa is Wrong it says E

any comments

KILL !! DIE !! or BEAT my FEAR !!! de@D END!!

Quote

Source: Beat The GMAT — Data Sufficiency | Sun Dec 14, 2008 1:19 am

vittalgmat: Legendary Member; Posts: 621; Joined: Wed Apr 09, 2008 7:13 pm; Thanked: 33 times; Followed by:4 members

by vittalgmat » Sun Dec 14, 2008 1:39 am

Vishubn
U almost got the correct solution... but fell into the classic
2 eqn 2 variable trap.

Stmt 1: j + k = 50k

insufficient.

stmt 2:
in 1985, each of their salaries were 10% more than their
corresponding prev yr salaries.

so
1.1j + 1.1k = 55k
=> 1.1(j+k) = 55k
=> j +k = 50k

insufficient.

combining them.
Both equations are identical.
hence no unique solutions.

therefore E

Here is the takeaway from this (from one of Ron/Stuart's comments)

The real "rule" in mathematics is this: If you have n *independent* *linear* equations and n unknowns, you can solve for all n of your unknowns. By "independent", we mean that you can't derive any one equation from the others.