What will come in the place of question mark(?) in the given expression?
​$$34^2 - 26^2 = ?^2 - \text{30 percent of } 320$$​​

Correct option is B

Given:
​$$34^2 - 26^2 = ?^2 - \left( \frac{30}{100} \times 320 \right)$$​​
Formula used:
​$$a^2 - b^2 = (a - b)(a + b), \quad \text{and} \quad x\% \text{ of } y = \frac{x}{100} \times y$$​​
Solution:
​$$\text{LHS: } 34^2 - 26^2 = (34 - 26)(34 + 26) = 8 \times 60 = 480 \\[5pt]\text{RHS: } ?^2 - \left( \frac{30}{100} \times 320 \right) = ?^2 - 96$$​​
Equating both sides:
​$$480 = ?^2 - 96 \\[5pt]\Rightarrow ?^2 = 480 + 96 = 576 \\[5pt]\Rightarrow ? = \sqrt{576} = 24$$​​
Correct answer is (b) 24.