Tuesday, September 21, 2010

Ann deposited money into two new accounts, A and B.Account A earns 5 percent simple annual interest and account B earns 8 percent simple annual interest. Ifthere were no other transactions in the two accounts, then the amount of interest that account B earned in the first year was how many dollars greater than the amount of interest that account A earned in the first year?

(1) Ann deposited $200 more in account B than in account A.

(2) The total amount of interest that the two accounts earned in the first year was $120.



statement 1: Pb = Pa + 200
insufficient by itself

statement 2: 0.05Pa + 0.08Pb = 120
insufficient by itself

both statements together: sufficient
(both statements are linear equations, and neither one is a multiple of the other; therefore, the 2x2 system has a unique solution)
there's no need to actually solve the system; all you have to do is note that you can solve it.

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