First, you will have to make some assumptions:

- that the moon does not get in between the Earth and the Sun during this particular day;

- that the sun 'shoots' out mass in every direction by the same amount;

- that the Earth actually gets all the mass that it comes into contact with;

- that the Earth is perfectly spherical;

- that the mass which goes through the atmosphere does not add to the mass gained.

and maybe more, just to make you understand that your method will not be 100% accurate, but usable just for an acceptable estimate

Second, you have to consider the mass just like power, and use the equation you use to determine the power. Ever heard of the equation I = P/A ? I is the intensity, P is the power. Let's say that the source of power is at the centre of the Sun, and it radiates mass in all directions.

1. Find the distance between the Sun and the Earth. This will give you a radius which you will use for the calculation of A, the area that the mass has covered when it reached the distance of the Earth.

2. Using I = P/A, but here, be sure that you understand that P is considered as being mass and I is the mass per unit area. This gives you something about mass/area (area is the area formula of a sphere, which is A = 4pi r^2)

3. Then, find the area of the Earth exposed to the mass, which becomes the area of a circle with the radius as the radius of the Earth.

4. From your initial answer (2) and your last answer (3), you should get the mass that the Earth got.

And since you worked with the mass expelled per day, your final answer is already with respect to a day.