Lodine-131 has a half-life of 8 days. If authorities found an original sample of 2.5 grams right after an emission from the plant how much iodine-131 would be left 30 days later?

How do you solving the solution of each system using elimination?

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Ateacher brought a pack of 17 batteries . each calculator uses 3 batteries . how many calculator can the teacher fill with batteries