Home›UPSC Prelims›Paper 2: General Studies II (CSAT)›Civil Services Aptitude Test (CSAT)›Basic Numeracy & Data Interpretation›Consider the following statements : 1. The sum of 5 consecutive

Consider the following statements :
1. The sum of 5 consecutive integers can be 100.
2. The product of three consecutive natural numbers can be equal to their sum.
Which of the above statements is/are correct ?

20213Mprelimsupscyear-2021p2quantitative-aptitudequantitative-abilitylinear-equation
A.(a) 1 only
B.(b) 2 only
C.(c) Both 1 and 2Correct
D.(d) Neither 1 nor 2
Explanation & Solution

Correct Option: (c) Both 1 and 2

Let's check Statement 1: 'The sum of 5 consecutive integers can be 100.' Let the 5 consecutive integers be x-2, x-1, x, x+1, x+2. Their sum is 5x. If 5x = 100, then x = 20. The integers are 18, 19, 20, 21, and 22. Their sum is indeed 100. Thus, Statement 1 is correct. Let's check Statement 2: 'The product of three consecutive natural numbers can be equal to their sum.' Let the three consecutive natural numbers be x-1, x, and x+1 (where x >= 2). Their product is (x-1)x(x+1) = x(x^2 - 1) = x^3 - x. Their sum is (x-1) + x + (x+1) = 3x. Setting product equal to sum: x^3 - x = 3x => x^3 - 4x = 0 => x(x^2 - 4) = 0. Since x is a natural number (x >= 2), x^2 - 4 = 0 => x = 2. The numbers are 2-1 = 1, 2, and 2+1 = 3. Let's check: Product = 1 * 2 * 3 = 6. Sum = 1 + 2 + 3 = 6. Both product and sum are equal to 6! Thus, Statement 2 is also correct. Therefore, both 1 and 2 are correct, making option (c) correct.

हिंदी में प्रश्न एवं आदर्श उत्तर

निम्नलिखित कथनों पर विचार कीजिए :
1. 5 क्रमागत पूर्णांकों का योगफल 100 हो सकता है ।
2. तीन क्रमागत धन-पूर्णांकों का गुणनफल उनके योगफल के बराबर हो सकता है ।
उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं ?

A.(a) केवल 1
B.(b) केवल 2
C.(c) 1 और 2 दोनोंसही
D.(d) न तो 1, न ही 2

सही उत्तर: (c) 1 और 2 दोनों

कथन 1 की जाँच: 5 क्रमागत पूर्णांकों का योग 100 हो सकता है। मान लीजिए संख्याएँ x-2, x-1, x, x+1, x+2 हैं, जिनका योग 5x है। यदि 5x = 100 है, तो x = 20। संख्याएँ 18, 19, 20, 21, 22 हैं जिनका योग 100 है। अतः कथन 1 सही है। कथन 2 की जाँच: तीन क्रमागत प्राकृतिक संख्याएँ x-1, x, x+1 हैं। इनका गुणनफल x(x^2 - 1) और योग 3x है। दोनों को बराबर करने पर: x^3 - x = 3x => x^3 - 4x = 0 => x = 2 (चूँकि प्राकृतिक संख्या है)। संख्याएँ 1, 2, 3 हैं। इनका गुणनफल (1 × 2 × 3 = 6) और योग (1 + 2 + 3 = 6) बराबर हैं। अतः कथन 2 भी सही है। विकल्प (c) सही है।

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