Student average score

[fueledGMAT]

A student took 7 tests. The student's average score on the first 5 tests was 73. The student's average score on the final 5 of these 7 tests was 79. How much greater than the student's average score on the first 2 of these tests was the student's average score on the final 2 of these tests?

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Thanks! Will post the answer shortly!

[shankar.ashwin]

Let the 7 tests be A,B,C,D,E,F and G.

Now marks of A+B+C+D+E = (5*73) = 365

Marks of C+D+E+F+G = 5*79 = 395

Now subtract these 2 equations, you have
F+G-A-B = 395-365

F+G-A-B = 30 -> F+G = (A+B) + 30.

Or last 2 tests = first 2 + 30

Or an average of 15 marks more per test. D IMO

[fueledGMAT]

You nailed it! Your explanation made way more sense than the Kaplan one. Thanks!

v/r

Shaun