Max@Math Revolution wrote:[GMAT math practice question]
How many integers between 50 and 100, inclusive, are divisible by 2 or 3?
A. 35
B. 37
C. 42
D. 47
E. 52
Total integers = (multiples of 2) + (multiples of 3) - (multiples of both 2 and 3).
For any evenly spaced set:
Count = (biggest - smallest)/increment + 1.
The INCREMENT is the difference between one value and the next.
Multiples of 2 between 50 and 100, inclusive:
Smallest = 50.
Biggest = 100.
Increment = 2.
Count = (100-50)/2 + 1 = 26.
Multiples of 3 between 50 and 100, inclusive:
Smallest = 51.
Biggest = 99.
Increment = 3.
Count = (99-51)/3 + 1 = 17.
Multiples of both 2 and 3 between 50 and 100, inclusive:
An integer divisible by both 2 and 3 is a MULTIPLE OF 6.
Thus:
Smallest = 54.
Biggest = 96.
Increment = 6.
Count = (96-54)/6 + 1 = 8.
Total integers = 26 + 17 - 8 = 35.
The correct answer is
A.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
