- 6. For the observation X1, X2 .....Xn; 1(xi 1) = 5n, the standard deviation of given data is (A) 10 (B) 5 (C) 2 (D) 3 7. The area of quadrilateral formed by the tangents at the ends of latus rectum of the ellipse 9x2 +16y = 144 is: 128 (A) 7 64 (B) (C) 27 3 167 (D) 11 8. The equation of the curve satisfying the differential equation y2(x + 1) = 2xy1 passing through point (3,0) and having slope of tangent at x = 0 as 2 is: (A) y = 2x- 4x - 6 23 (C) y=x + 2x - 24 3 (B) 3yx3 - 12x - 3 2 2 (D) 3y = x + x = 21 3