UPSC Prelims 2007 · General Studies
Question 143: Basic Numeracy
Six equidistant vertical lines are drawn on a board. Six equidistant horizontal lines are also drawn on the board cutting the six vertical lines and the distance between any two consecutive horizontal lines is equal to that between any two consecutive vertical lines. What is the maximum number of squares thus formed?
AnswerThe answer is (b).
Six vertical and six horizontal lines make a 5 by 5 grid of small squares. Count squares of each size: 1x1 gives 25, 2x2 gives 16, 3x3 gives 9, 4x4 gives 4, and 5x5 gives 1. The total is 25 + 16 + 9 + 4 + 1 = 55.
Why each option is right or wrong
- (a) 37 is too low; the count is 55.
- (b) Correct: 25 + 16 + 9 + 4 + 1 = 55.
- (c) 126 is too high; the count is 55.
- (d) 225 is too high; the count is 55.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2007, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.