Question
The average Economics marks of two sections A and B of
class X in the annual examination is 70. The average marks of Section A is 72.5 and that of section B is 68. The ratio of the number of students of section A and B isSolution
Let the number of students in section A is x and B is y, then  70 = (72.5 × x + 68 × y)/ (x + y)  ⇒ 70x + 70y = 72.5x + 68y  ⇒ 2y = 2.5x   ⇒ x/y = 2/2.5  ⇒ x/y = 4 : 5
The value of 0∫π cos3x dx is –
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