Post your question in the Comment section below, and a GRE expert will answer it as fast as humanly possible.
- Video Course
- Video Course Overview
- General GRE Info and Strategies - 7 videos (free)
- Quantitative Comparison - 7 videos (free)
- Arithmetic - 42 videos
- Powers and Roots - 43 videos
- Algebra and Equation Solving - 78 videos
- Word Problems - 54 videos
- Geometry - 48 videos
- Integer Properties - 34 videos
- Statistics - 28 videos
- Counting - 27 videos
- Probability - 25 videos
- Data Interpretation - 24 videos
- Analytical Writing - 9 videos (free)
- Sentence Equivalence - 39 videos (free)
- Text Completion - 51 videos
- Reading Comprehension - 16 videos
- Study Guide
- Philosophy
- Office Hours
- Extras
- Prices
Comment on Mutually Exclusive Events
i don't understand mutually
Is there a specific part of
Is there a specific part of that example you don't understand?
Dear Sir,
If x^2 +2x-15 = -m , and x is an integer between -10 and 10 . What is the probability that m is greater than zero ?
I tried to solve this question by solving for the roots but i am having hard time to get the correct answer . Would please help me to solve this one.
Regards
Shubham
Given: -m = x^2 + 2x - 15
Given: -m = x^2 + 2x - 15
Factor: -m = (x + 5)(x - 3)
So, there are three ranges of x-values to consider:
1) x < -5
2) -5 < x < 3
3) 3 < x
1) x < -5
When x < -5, (x + 5)(x - 3) is POSITIVE, which means m is NEGATIVE
2) -5 < x < 3
When -5 < x < 3, (x + 5)(x - 3) is NEGATIVE, which means m is POSITIVE
3) 3 < x
When 3 < x, (x + 5)(x - 3) is POSITIVE, which means m is NEGATIVE
So, m is positive only when -5 < x < 3
Since x is an integer, then the possible values of x are: -4, -3, -2, -1, 0, 1 and 2 (7 values)
The question says "x is an integer between -10 and 10 . What is the probability that m is greater than zero ?"
So, there are 19 integers BETWEEN -10 and 10
Of those 19 x-values, 7 of them are such that m evaluates to be positive.
So, P(m is positive) = 7/19
I think, in factorization it
x possible values would be -4 -3 -2 -1 0 1 & 2. isn't it?
but how to tell the probability?
Good catch! I've edited my
Good catch! I've edited my response above.