Abox of 10 markers weighs 105 grams. if the empty box weights 15 grams, how much does each marker weigh?

First, ,how much do all the markers weight? the box with the markers weights 105, so without the box all the markers weigh 105-15=90 grams.

so 90 grams is the weight of 10 markers together, and each of them will weigh one tenth of this: 90/10=9

so each marker weights 9 grams.

If the diameter is 8 than the radius is 4 because 2r or 2*radius equals the diameter. 4*2=8. 8/2=4.