The position of the image formed by the combination of lenses is 

$$\text{First lens: } u_1 = -30\text{ cm},\ f_1 = +10\text{ cm} \implies \frac{1}{v_1} - \frac{1}{-30} = \frac{1}{10} \implies v_1 = +15\text{ cm}$$

$$\text{Second lens: } u_2 = +(15 - 5) = +10\text{ cm},\ f_2 = -10\text{ cm} \implies \frac{1}{v_2} - \frac{1}{10} = \frac{1}{-10} \implies v_2 = \infty$$

$$\text{Third lens: } u_3 = \infty,\ f_3 = +30\text{ cm} \implies \frac{1}{v_3} - \frac{1}{\infty} = \frac{1}{30} \implies v_3 = +30\text{ cm}$$