In school A, the ratio of total number of girls to the

Solution

In school A, Let total number of pencils and pens used be px and qx respectively. According to the question, => px – qx = 40 => 120 – qx = 40 => qx = 80 Ratio = px : qx = 120 : 80 = 3:2 Total number of pencils used = px = 120 Total number of pens used = qx = 80 In school B, Let total number of pencils and pens used be 3x and 2x respectively. According to the question, => 3x – 2x = 90 => x = 90 So, 3x = 270 and 2x = 180 Now, (m² + 45) = 270 => m² = 225 => m = 15 Total number of pencils used = 3x = 270 Total number of pens used = 2x = 180 In school C, Let total number of pencils and pens used be gx and hx respectively. According to the question, => gx = 8m – 70 => gx = (8 × 15) – 70 => gx = 50 So, hx = 50 – 20 = 30 Ratio = gx : hx = 50 : 30 = 5:3 Total number of pencils used = gx = 50 Total number of pens used = hx = 30 In school D, Let total number of pencils and pens used be tx and x respectively. According to the question, => tx = 75 So, tx – x = 50 => 75 - x = 50 => x = 25 Ratio = tx : x = 75 : 25 = 3:1 Total number of pencils used = tx = 75 Total number of pens used = x = 25 Total number of girls in school A = (h/2) × 160 = (3/2) × 160 = 240 Total number of children in school A = 240 + 160 = 400 Total number of pencils and pens used = 120 + 80 = 200 Number of children who did not used any of the stationary items = 400 – 200 = 200