Which of the following fractions is reducible, that is, not in its lowest terms?

Introduction / Context:
This question checks whether you can recognize a fraction that is not in simplest form. Simplifying fractions, or checking if they are reducible, is a frequent step in many aptitude calculations.

Given Data / Assumptions:

• Fractions given: 79/26, 105/112, 41/17 and 91/15.
• We need to identify the fraction that can be simplified further.
• A reducible fraction has a numerator and denominator with a common factor greater than 1.

Concept / Approach:
A fraction is in lowest terms if the greatest common divisor of numerator and denominator is 1. To test reducibility, we factor the numerator and denominator or at least check for obvious common factors such as 2, 3, 5, 7 and 11.

Step-by-Step Solution:

Verification / Alternative check:
If we compute the greatest common divisor of each pair, only gcd(105, 112) is greater than 1. This confirms that 105/112 is the only reducible fraction.

Why Other Options Are Wrong:
79/26, 41/17 and 91/15 have numerators and denominators that are relatively prime. They are already in lowest terms and therefore are not reducible.

Common Pitfalls:
Students often confuse reducibility with the size of the fraction or with whether it is proper or improper. A fraction can be large or improper and still be in simplest form. What matters is the common factors of numerator and denominator.

Final Answer:
The only fraction that can be reduced further is 105/112.