Question

Nancy and Monica participated in a test series from January to September. Their marks are plotted on a line graph. What is the average difference between the marks obtained by them during the entire test series?

• A. 16.33
• B. 18.77
• C. 16.50
• D. 17.77

Answer 1

The correct option is D 17.77

Let's plot the data in tabular form.

Average difference
= $\frac{\text{Sum of difference}}{\text{Total months}}$

Sum of difference
= 10 + 10 + 0 + 10 + 30 + 40 + 30 + 20 + 10 = 160

= $\frac{\text{160}}{\text{9}}$

= 17.77