Practicing Success
The average mathematics marks of two sections A and B of class IX in the annual examination is 74. The average marks of section A is 77.5 and that of section B is 70. The ratio of the number of students of section A and B is: |
7 : 8 7 : 9 8 : 7 8 : 9 |
8 : 7 |
If the number of students in section A be p and that in section B be q, then According to question, 74 = \(\frac{ 75.5 \; × \; p\; + \;q \; × \; 70}{ p \; + \;q}\) ⇒ 74p + 74q = 77.5p + 70q ⇒ 77.5p – 74p = 74q – 70q ⇒ 3.5p = 4q \(\frac{p}{q}\) = \(\frac{8}{7}\) |