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Arithmetic looks like the easy part of GMAT Quant, which is exactly why it is dangerous: the test writers hide difficulty in fractions, percents, ratios, and remainders rather than in advanced math. These Problem Solving questions drill the number sense the rest of Quant is built on — decimal and fraction manipulation, percent change, ratio splits, and divisibility. If your accuracy here is below 90%, fix that before touching harder topics; arithmetic errors are the most common source of lost points on questions you knew how to solve.
Divisibility, remainders, factors, multiples.·Show:203050 655-705 (Hard)
In the first week of the year, Nancy saved $1. In each of the next 51 weeks, she saved $1 more than she had saved in the previous week. What was the total amount that Nancy saved during the 52 weeks?
655-705 (Hard)
For any positive integer n, the sum of the first n positive integers equals 2n(n+1). What is the sum of all the even integers between 99 and 301?
655-705 (Hard)
1.00010.99999999−1.00030.99999991=
655-705 (Hard)
List T consists of 30 positive decimals, none of which is an integer, and the sum of the 30 decimals is S. The estimated sum of the 30 decimals, E, is defined as follows. Each decimal in T whose tenths digit is even is rounded up to the nearest integer, and each decimal in T whose tenths digit is odd is rounded down to the nearest integer; E is the sum of the resulting integers. If 31 of the decimals in T have a tenths digit that is even, which of the following is a possible value of E−S?
I. −16
II. 6
III. 10