CAT 2022 Quant was dominated by Arithmetic followed by Algebra. In Arithmetic, the questions were dominated by topics like Speed-time-distance, Mixture and Alligations. This year, there was a surprise. The questions from Geometry were relatively on the lower side as compared to the previous years. There were 8 TITA Qs this year. Overall this section was at a medium level of difficulty.
Question 7 : The average of three integers is 13 . When a natural number \(n\) is included, the average of these four integers remains an odd integer. The minimum possible value of \(n\) is
Let the four integers be \(I_1, I_2, I_3\) and \(I_4\).
We know that the average of \(I_1, I_2, I_3\)is 13.
If \( I _ { 4 } \)is also 13, the average will be unchanged. The new average is also 13.
If \( I _ { 4 } \) is 13 + 4, the average will increase by 1. The new average is 14.
If \( I _ { 4 } \) is 13 + 4(2), the average will increase by 2. The new average is 15.
If \( I _ { 4 } \) is 13 + 4(x), the average will increase by x. The new average is 13 + x.
If \( I _ { 4 } \) is 13 - 4, the average will decrease by 1. The new average is 12.
If \( I _ { 4 } \) is 13 - 4(2), the average will decrease by 2. The new average is 11.
If \( I _ { 4 } \) is 13 - 4(x), the average will decrease by x. The new average is 13 - x.
We observe that for the average to remain odd and an integer, \( I _ { 4 } \) should be \( 13 \pm 8 x \) where x is a whole number. Since we intend to find the smallest value of \( I _ { 4 } \), the question transpires to be What is the maximum value of x such that 13 - 8x is a natural number?
The maximum value of x is 1. Therefore, the minimum value of 13 - 8x is 5.
That minimum value of \( I _ { 4 } \) such that it satisfies all the given conditions is 5.
The question is " The average of three integers is 13 . When a natural number \(n\) is included, the average of these four integers remains an odd integer. The minimum possible value of \(n\) is "
Choice C is the correct answer.
Copyrights © All Rights Reserved by 2IIM.com - A Fermat Education Initiative.
Privacy Policy | Terms & Conditions
CAT® (Common Admission Test) is a registered trademark of the Indian Institutes of Management. This website is not endorsed or approved by IIMs.
2IIM Online CAT Coaching
A Fermat Education Initiative,
58/16, Indira Gandhi Street,
Kaveri Rangan Nagar, Saligramam, Chennai 600 093
Mobile: (91) 99626 48484 / 94459 38484
WhatsApp: WhatsApp Now
Email: info@2iim.com