What is the difference between the total number of males and females in the building?

Solution

Let the number of people who read ‘The Hindu and TOI (Only)’ be x Let the number of people who read ‘The Hindu and Economic Times (Only)’ be y. Let the number of people who read ‘TOI and Economics Times (Only)’ be z. Given that: 40 + 20 +x +y = 100 =>x+y = 40 ---- (i) 70 + 20 +x+z = 150 =>x+z = 60 ----(ii) 100 + 20 +y+z = 200 =>y+z = 80 -----(iii) Adding eq. (i), (ii) and (iii), we get 2 (x+y+z) = 180 x+y+x = 90 ----(iv) Now, subtracting (iv) by (i), we get z= 50 Now, subtracting (iv) by (ii), we get y= 30 Now, by subtracting (iv) by (iii), we get X=10 Total number of males =5/8 of 40 + 7/10 of 70 + 11/20 of 100 + 4/5 of 10 + 7/15 of 30 +2/5 of 50+ 3/4 of 20 Total number of females = 320 - 186 = 134 Required difference = 186 – 134 = 52