Answer:
Nirmala can use the lamp for 31.66 hours before it runs out of oil.
Step-by-step explanation:
From the graph,
Take any two points, let say
(15, 25)
(25, 10)
The equation of line in slope-intercept form
Putting and any point, let say (25, 10), to find the y-intercept 'b'
So the equation of line will be:
In order to find how long Nirmala can use the lamp before it runs out of oil, we need to find x-intercept which can be obtained by putting y = 0, and solve for x, as duration lies on x-axis.
so
Putting y = 0
Therefore, Nirmala can use the lamp for 31.66 hours before it runs out of oil.