A sample originally contains 21 grams of a radioactive isotope. After 45 days, 17.3 grams of the isotope remain in the sample.

Mathematics

2 answers:

Darya [45]3 years ago

4 0

Answer:

The answer to your question is: 128 days

Step-by-step explanation:

Data

original mass = 21 g

after 45 days = 17.3 g

Process

mass transform = 21 - 17.3 = 3.7 g

21 g ----------------------- 100 %

3.7 g --------------------- x

x = (3.7 x 100) / 21

x = 17.61 %

17.61 % ------------------- 45 days

50% -------------------- x

x = (50 x 45) / 17.61

x = 127.8 ≈ = 128 days

AlekseyPX3 years ago

3 0

Answer:

It is actually 161

You might be interested in

If Pentagon ABCDE was dilated to create Pentagon A'B'C'DE', what rule was used?

svetlana [45]

Answer:

B $(x,y) \rightarrow \left(\frac{5}{2}x,\frac{5}{2}y\right)$

Step-by-step explanation:

Dilations

Given a point A(x,y) and a scale factor k the dilated image of A, called A' is calculated as A'=(kx,ky), assuming the same scale factor is applied in both axes.

The pentagon ABCDE was dilated to create pentagon A'B'C'D'E'. To find the dilaton rule used, we must find two clear points where the coordinates of both axes can be easily read from the graph.

Point C(-2,0) maps to C'(-5,0). This gives us the scale factor for the x-axis of -5/(-2)= 5/2.

The y-coordinate of E is 2 and the y-coordinate of E' is 5. This gives us the same scale factor for the y-axis of 5/2.

Thus, the rule to dilate the pentagon is:

B $\mathbf{(x,y) \rightarrow \left(\frac{5}{2}x,\frac{5}{2}y\right)}$