Question

An element with mass 330 grams decays by 25.5% per minute. How much of the element is remaining after 5 minutes, to the nearest 10th of a gram?

Answer 1

Answer:

After 5 minutes, it remains 75.73 grams of mass.

Step-by-step explanation:

Each minute, the mass is decreased by a 25.5%. So, we can find the mass after each minute period.

First minute.

$330gr-0.255(330gr)=(330-84.15)gr=245.85 gr$

Second minute.

$245.85-0.255(245.85)=245.85-62.69=183.16gr$

Third minute.

$183.16-0.255(183.16)=183.16-46.70=136.45gr$

Fourth minute.

$136.45-0.255(136.45)=136.45-34.80=101.65$

Fifth minute.

$101.65-0.255(101.65)=101.65-25.92=75.73gr$

Therefore, after 5 minutes, it remains 75.73 grams of mass.

Answer 2

Equation: 330-.255(5)=X. Multiply: .255(5)=1.275, 330-1.275=X. Subtract: 330-1.275=328.725 or 328.73 :)