An element with mass 130 grams decays by 22% per minute. How much of the element is remaining after 7 minutes, to the nearest 10th of a gram?

The answer to your question is 22.9 g

Step-by-step explanation:

Data

mass = 130 g

rate = 22%

time = 7 min

Process

1.- Calculate the mass remaining after each minute

                   130 g 100

                     x         22

                     x = (22 x 130) / 100

                    x = 28.6 g

mass remaining = 130 - 28.6 = 101.4 g

                   101.4 g 100

                      x       22

                      x = (22 x 101) / 100

                      x = 22.22

mass remaining = 101.4 - 22.22

                           = 79.18

                     79.18 g 100

                           x       22

                          x = (22 x 79.18)/100

                          x = 17.41

mass remaining = 79.18 - 17.41

                           = 61.76

                       61.76 100

                           x      22

                           x = (22 x 61.76)/100

                           x = 13.59

mass remaining = 61.76 . 13.59

                           = 48.17 g

                         48.17 g 100

                              x         22

                              x = (22 x 48.17)/100

                              x = 10.59

mass remaining = 48.17 - 10.59

                           = 37.57 g

                          37.57 g 100

                              x       22

                              x = (22 x 37.57) / 100

                              x = 8.26 g

mass remaining = 37.57 - 8.26

                           = 29.3

                           29.3 g 100

                               x     22

                               x = (22 x 29.3)/100

                               x = 6.45

mass remaining = 29.3 - 6.45

                           = 22.85 g

2/3

step-by-step explanation:

the slope of a line is equal to the rise/run. in this case the line rises 2 units for every +3 units it moves

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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