• # question_answer How many coins 1.4 cm in diameter and 0.4 cm thick is to be melted to form, right circular cylinder of height 16 cm and diameter 3.5 cm A)  200                             B)  150            C)  250       D)  300

(c): no. of corns = $\frac{\pi {{R}^{2}}H}{\pi {{r}^{2}}h}=\frac{{{(3.5)}^{2}}\times 16}{{{(1.4)}^{2}}\times 0.4}$ $={{\left( \frac{5}{2} \right)}^{2}}\times 40$ $=\frac{25}{4}\times 40=250.$