Question

The given graph shows the relation between time (in days) and number of two wheeler breaking the traffic rules in a particular signal. On which days the number of two wheelers breaking the rules is decreasing?

• A. 10th day and 11th day
• B. 9th day and 10th day
• C. 10th day and 12th day
• D. 8th day and 10th day

Answer 1

The correct option is B 9th day and 10th day

Let us look at the given graph:


We know,
$\text{Rate of change}=\frac{\text{Change in y}}{\text{Change in x}}$

From Day 0 to Day 2:
For the starting two days, the rate of two wheelers breaking rules per day = $\frac{4-0}{2-0}=2$

Here, a positive slope indicates an increase in the number of vehicles that are breaking the rules.

From day 2 to day 6:
The number of two wheelers breaking the rules is constant as the slope is zero.

From day 6 to day 8:
The rate of two wheelers breaking the $\text{rules per day is}=\frac{6-4}{8-6}=1$

Here, a positive slope indicates an increase in the number of vehicles that are breaking the rules.

From day 8 to day 10:
The rate of two wheelers breaking rules $\text{per day is}=\frac{0-6}{10-8}=-3$

Here, a negative slope indicates a decrease in the number of vehicles that are breaking the rules.

Therefore, for the 9th and the 10th day, the number of two wheelers breaking the rules has decreased.