Question

Mary invests £12000 in a savings account.

Answer 1

Using a proportional relationship, it is found that:

a) The equation is: y = 63/x.

b) When x = 21, the numeric value is of y = 3.

What is a proportional relationship?

A proportional relationship is a special case of a linear function, with slope represented by the constant of proportionality of k and intercept of 0.

When the two variables are inversely proportional, we have a inverse proportional relationship, in which the output variable y is obtained by the division of k by the input variable x, as follows:

y = k/x.

For this function, when y = 7, x = 9, hence the constant is obtained as follows:

7 = k/9

k = 9 x 7

k = 63.

Hence the equation is:

y = 63/x.

The numeric value of the function when x = 21 is given as follows:

y = 63/21 = 3.

More can be learned about proportional relationships at brainly.com/question/10424180

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