rxs0005
For integers a , b, c , a / b - c = 1 what is the value of b - c / b ?
S1 a / b = 3/ 5
S2 a and b have no common factors greater than 1
rxs0005 format the questions properly!Question should read:
For integers a , b, c, a/(b - c)=1 what is the value of (b-c)/b ?Given: \(\frac{a}{b-c}=1\) --> \(a=b-c\). Question: \(\frac{b-c}{b}=\frac{a}{b}=?\) So basically we need the value of \(\frac{a}{b}\).
(1) a/b=3/5. Sufficient.
(2) a and b have no common factors greater than 1 --> \(a\) and \(b\) are co-prime, so \(\frac{a}{b}\) could take multiple values. Not sufficient.
Answer: A.
fluke
For integers a , b, c , a / b - c = 1 what is the value of b - c / b ?
\(\frac{a}{b-c}=1\)
\(a=b-c\)
\(\frac{a}{b} = \frac{b-c}{b}\) ====> Dividing both sides by b(Because the question asks; \(\frac{b-c}{b}\), we can assume(or we can't) that b is non-zero
Q: What is \(\frac{a}{b}\)
1. a / b = 3/ 5 : Sufficient.
2. a and b are prime numbers;
a/b can be 13/11.
or
a/b can be 17/13.
Not sufficient.
Ans: "A"
From (2) \(a\) and \(b\) are not necessarily prime numbers they are co-prime numbers (numbers which don't share ANY common factor but 1), so each can be non-prime as well for example: \(a=8\) and \(b=9\).