Question

this graph shows how the accuracy of jasmines watch is related to how long its been since she last set it. how many days has it been since jasmine last set her watch if the watch is 30 seconds behind? 2 days 1 day 3 days 4 days

Explanation:

Step1: Identify linear equation form

The graph is a line, so use $y = mx + b$, where $y$ = seconds behind, $x$ = days, $b=20$ (y-intercept).

Step2: Calculate slope $m$

Use points $(0,20)$ and $(10,68)$:
$m = \frac{68-20}{10-0} = \frac{48}{10} = 4.8$
Equation: $y = 4.8x + 20$

Step3: Solve for $x$ when $y=30$

Substitute $y=30$:
$30 = 4.8x + 20$
$4.8x = 30 - 20 = 10$
$x = \frac{10}{4.8} \approx 2.08$
Round to nearest whole day: 2 days

Step4: Verify with graph

Check the line: at 30 seconds behind, the corresponding $x$-value is 2 days.

Answer:

A. 2 days