P = (P*30*R)/100
R = 3 1/3%
At what rate percent on simple interest will a sum of money double itself in 30 years?
Options:
(A) 3 1/3%
(B) 8 1/3%
(C) 3 5/3%
(D) 5 1/3%
(E) 3 1/7%
(A)

Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8.
The no. of girls in a class are 7times the no. of boys, which value cannever be the of total students?
Options:
(A) 20
(B) 35
(C) 30
(D) 40
(E) 42
(C)

1/5:1/5:1/10 = 2:2:1
1/5*5000 = 1000
2000-1000 = 1000
Rs. 5000 is divided into three parts A, B and C. How much A is more than C if their ratio is 1/5:1/5:1/10?
Options:
(A) 1000
(B) 992
(C) 772
(D) 552
(E) 312
(A)