Question

Please help with this question I’ve been stuck on it if you can’t see click the picture it will make it a little bit bigger

Answer 1

Answer:

The option '$20 a month' is the correct option.

Step-by-step explanation:

The slope-intercept form of the line equation

$y = mx+b$

where

• m is the rate of change or slope

• b is the y-intercept

Given that Marta has opened a saving account with $25.

In other words, the initial condition of the function is $25.

Thus, the y-intercept b = 25

Let y be the total amount

Let x be the number of months

Given that at the end of three months, she has $85 in her account.

so we get the point (x, y) = (3, 85).

Now, in order to determine the rate of change or slope, substitute x = 3, y = 85 and b = 25 in the slope-intercept form of the line equation to determine the rate of change or slope

y = mx + b

85 = m(3) + 25

85 = 3m + 25

switch sides

3m + 25 = 85

subtract 25 from both sides

3m + 25 - 25 = 85 - 25

3m = 60

divide both sides by 3

3m/3 = 60/3

m = 20

so, the rate of change is $20 a month.

Thus, Marta has been making deposits at the rate of $20 a month to her savings.

Therefore, the option '$20 a month' is the correct option.