If $\dfrac{a}{3} = \dfrac{b}{4} = \dfrac{c}{7}$, then $\dfrac{a + b + c}{c}$ = ?

1. $\dfrac{1}{2}$

2. $\dfrac{1}{7}$

3. 2

4. 7

If x, 5.4, 5, 9 are in proportion, then x is equal to:

1. 3

2. 9.72

3. 25

4. $\dfrac{25}{3}$

The fourth proportional to 0.12, 0.21 and 8 is :

1. 8.9

2. 14

3. 17

4. 56

The third proportional to 38 and 15 is :

1. $\dfrac{15}{38 \times 38}$

2. $\dfrac{38 \times 38}{15}$

3. $\dfrac{15 \times 15}{38}$

4. $\dfrac{38 \times 15}{2}$