RRB JE 30th May 2019 Shift-2

Question 66

Which of these square numbers cannot be expressed as the sum of two prime numbers?

Solution

odd + odd = even

odd + even = odd

2 is the only prime number, so if the sum of distinct prime numbers is odd, one of them must be 2 and sum of 2 and an odd number is odd

odd

a. 81 = 79 + 2

79 is a prime number , 81 is the not the answer

b. 121 = 119 + 2 

   119 is a prime number , 121 is not the answer

c.144 = 142 + 2 , 142 is not a prime number so 144 is the answer

d.49 = 47 + 2 

47 is a prime number , 49 cannot be the answer


Create a FREE account and get:

  • Download RRB Study Material PDF
  • 45+ RRB previous papers with solutions PDF
  • 300+ Online RRB Tests for Free

CAT Quant Questions | CAT Quantitative Ability

CAT DILR Questions | LRDI Questions For CAT

CAT Verbal Ability Questions | VARC Questions For CAT

Free CAT Topicwise Questions

CAT Arrangement

CAT Logarithms, Surds and Indices

CAT Time And Work

CAT Venn Diagrams

CAT Profit, Loss and Interest

CAT Averages, Ratio and Proportion

CAT Mensuration

CAT Number Series

CAT Selection With Condition

CAT Grammar and Sentence Correction

CAT Routes And Networks

CAT Critical Reasoning

CAT Percentages

CAT Para Summary

CAT Miscellaneous LR

CAT Data Sufficiency

CAT Profit And Loss

CAT Coordinate Geometry

CAT Charts

CAT Scheduling

CAT Simple Interest Compound Interest

CAT Miscellaneous

CAT Data change over a period

CAT Puzzles

CAT Arithmetic

CAT Time Speed Distance

CAT 2D & 3D LR

CAT Number Systems

CAT Truth Lie Concept

CAT Inequalities

CAT Coins and Weights

CAT DI with connected data sets

CAT Time, Distance and Work

CAT Quant Based DI

CAT Data Interpretation Basics

CAT Odd One Out

CAT Logarithms

CAT Averages

CAT Averages Mixtures Alligations

CAT Linear Equations

CAT Venn Diagrams

CAT Probability, Combinatorics

CAT Vocabulary

CAT Table with Missing values

CAT Verbal Ability

CAT Progressions and Series

CAT Remainders

CAT Reading Comprehension

CAT Special Charts

CAT Functions, Graphs and Statistics

CAT Ssc Reasoning

CAT Para Jumbles

CAT DI Miscellaneous

CAT Maxima-Minima

CAT Quadratic Equations

CAT Quant Based LR

CAT Games and Tournamnents

CAT Algebra

CAT Data Interpretation

CAT Geometry

cracku

Boost your Prep!

Download App