Quantitative | Re: Overview of GMAT Math Question Types and Patterns on the GMAT

[GMAT math practice question]

(arithmetic) What is 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56?

A. 3/5
B. 5/8
C. 7/8
D. 8/9
E. 9/10

=>

1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56
= 1/(1*2) + 1/(2*3) + 1/(3*4) + 1/(4*5) + 1/(5*6) + 1/(6*7) + 1/(7*8)
= (1/1 – 1/2) + (1/2 – 1/3) + (1/3 – 1/4) + (1/4 – 1/5) + (1/5 – 1/6) + (1/6 – 1/7) + (1/7 – 1/8)
= 1/1 – 1/8 = 7/8

Therefore, C is the answer.
Answer: C

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