Since there is a 1 out of 6 chance to get a black sock and 24 divided by 6 is 4, there are 4 socks that are black.
Mass = density x volume
Mass = 178 x 25 = 4,450 grams
The sum of angles in a triangle is 180°, so we have an equation
2*35° + x = 180°
x = 180°-70° = 110°
The third angle is 110°