Saved Bookmarks
| 1. |
The ratio between the number of students in class I and II is 8 : 5, that between the number of students in class II and III is 3 : 4 and that between the number of students in class III and IV is 7 : 8. If the difference between the number of students in class II and IV is 33, then the number of students in class III is:1. 682. 903. 844. 76 |
|
Answer» Correct Answer - Option 3 : 84 Given: The number of students in class I and II is 8 : 5 The number of students in class II and III is 3 : 4 The number of students in class III and IV is 7 : 8 Difference between the number of students in class II and IV is 33 Calculation: Let the number of students in class I is 8x Number of students in class II = 8x × 5/8 = 5x Number of students in class III = 5x × 4/3 = 20x/3 Number of students in class IV = 20x/3 × 8/7 = 160x/21 160x/21 – 5x = 33 ⇒ (160x – 105x)/21 = 33 ⇒ 55x/21 = 33 ⇒ x = (33 × 21)/55 ⇒ x = 12.6 ⇒ Number of students in class III = (20 × 12.6)/3 = 84 ∴ Number of students in class III is 84 |
|