Answer
a. Step-up
b. 3.2
Work Step by Step
a. Assume a lossless situation. Find the input voltage from P=IV and the input current.
$$V_{primary}=\frac{P}{I_{primary}}=\frac{95W}{25A}=3.8V$$
The step-up transformer changed 3.8 volts to 12 volts.
b. The voltage is multiplied by the ratio 12/3.8, or 3.2.
