Answer:
Δf = 0.00003 MHz = 30 Hz
Step-by-step explanation:
The apparent frequency due to the motion of receiver towards the source is given by Doppler's effect, while the source is stationary. Therefore, the formula is given as follows:

where,
f = apparent frequency
c = speed of light = 3 x 10⁸ m/s
v₀ = velocity of observer = 46 m/s
f₀ = Original Frequency = 175 MHz = 175 x 10⁶ Hz
Therefore,

f = 175.00003 MHz
Therefore, the change in frequency is:
Δf = f - f₀
Δf = 175.00003 MHz - 175 MHz
Δf = 0.00003 MHz = 30 Hz