Question : If a : b = 4 : 5 and b : c = 3 : 10, then a : c is:

Option 1: 4 : 10

Option 2: 5 : 3

Option 3: 25 : 6

Option 4: 6 : 25

Question : If A : B = $\frac{1}{2}:\frac{1}{3}$, B : C = $\frac{1}{5}:\frac{1}{3}$ ,then (A + B) : (B + C) is equal to:

Option 1: 5 : 8

Option 2: 9 : 10

Option 3: 15 : 16

Option 4: 6 : 15

Question : If A : B = 2 : 5, B : C = 4 : 3, and C : D = 2 : 1, what is the value of A : C : D?

Option 1: 6 : 5 : 2

Option 2: 7 : 20 : 10

Option 3: 8 : 30 : 15

Option 4: 16 : 30 : 15

Question : The average of a, b, and c is 20, and that of b, c, and d is 25. If d = 30, then the value of a is:

Option 1: 25

Option 2: 45

Option 3: 30

Option 4: 15

Question : If $a^2+b^2+c^2=16$, $x^2+y^2+z^2=25$ and $ax+by+cz=20$, then the value of $\frac{a+b+c}{x+y+z}$ is:

Option 1: $\frac{3}{5}$

Option 2: $\frac{5}{3}$

Option 3: $\frac{4}{5}$

Option 4: $\frac{5}{4}$