Step-by-Step Solution
Key Concept: Assumed mean / step-deviation method for mean. Modal class $160-180$ for mode.
Table setup with class marks $x_i$, $f_i$, step-deviations $u_i$. Total $\sum f_i = 110$, $\sum f_i u_i = 1$. [2.0 Marks]
$\text{Mean} = A + h \left(\dfrac{\sum f_i u_i}{\sum f_i}\right) = 170 + 20\left(\dfrac{1}{110}\right) = 170.18$. [1.5 Marks]
Modal class $160-180$. $l = 160, f_1 = 22, f_0 = 20, f_2 = 18, h = 20$.
$\text{Mode} = 160 + \left(\dfrac{22 - 20}{44 - 20 - 18}\right) \times 20 = 160 + \dfrac{40}{6} = 166.67$. [1.5 Marks]
Correct Answer: Mean $= ₹170.18$, Mode $= ₹166.67$