Can someone please help me with this its VERY important

Ageologist had two rocks on a scale that weighed 4.6 kilograms together.rock a was 0.5 of the total weight.how much did rock a weigh?

Evaluate the expression. (9 + 5)(3 + 2)0

The distribution of a sample of the outside diameters of pvc pipes approximates a symmetrical, bell-shaped distribution. the arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches. about 68% of the outside diameters lie between what two amounts?