The population of a new city is 5 million and is growing at 20% annually. How many years would
it take to double at this growth rate?
Options:
(A) 3-4 years
(B) 4-5 years
(C) 5-6 years
(D) 6-7 years
Q. 6 – Q. 10 carry two marks each.
Official Answer Key:
B
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2014 Q.60)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **MCQ** (2 Marks)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Systematic Conceptual & Option-by-Option Evaluation**:
- Problem Focus: *"If a plant is shifted to cold temperature, which of the following changes would take place in its
membrane?..."*
- **Option (B) [CORRECT]**: *"Ratio of unsaturated to saturated fatty acids would decrease"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"Ratio of unsaturated to saturated fatty acids would increase"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (C) [INCORRECT]**: *"Absolute amount of both fatty acids would increase keeping the ratio same"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"Absolute amount of both fatty acids would remain unchanged"* does not satisfy the precise boundary conditions or molecular specificity.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **B**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.66 marks).
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