If 15% of 80 - 36 × 3√216 × √36 = y, then the value of y is:

Simplify the expression: √(890 + √(91 + √(47 + √(1142 + √(196)))))

What should come in place of the question mark (?) in the following expression? √9604 × √1369 × √529 ÷ √2401 = ?

√0.0625 ÷ √0.250 =