For your party you purchased balloons for $.79 each. you spent a total of $11.85. about how many balloons were purchased?

Let us suppose the number of balloons purchased is x in number.

It is given balloons are purchased for $.79 each

Cost of x balloons = .79x.

Total amount spent on purchasing balloons = $11.85

Cost of x balloons = Total cost of balloons.

.79x=11.85

With x .79 is multiplied .Opposite of multiplication is division.

We perform the opposite operation both sides

Dividing both sides by .79

x=11.85÷.79

x=15

Total number of balloons purchased is 15.

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

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