Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: 2007 · Marks: · Difficulty:
A well with inner diameter 8 m is dug 14 m deep. Earth taken out of its has been evenly spread all around it to a width of 3 m to form an embankment. The height of the embankment will be
(a)$4 \frac{26}{33} \mathrm{m}$
(b)$5 \frac{26}{33} \mathrm{cm}$
(c)$6 \frac{26}{33} \mathrm{cm}$
(d)$7 \frac{26}{33} \mathrm{cm}$
Answer
Answer (as printed): C
Explanation
Volume of earth dug out $=\left(\frac{22}{7} \times 4 \times 4 \times 14\right) \mathrm{m}^{3}=704 \mathrm{m}^{3}$. Area of embankment $$=\frac{22}{7} \times\left(7^{2}-4^{2}\right)=\left(\frac{22}{7} \times 11 \times 3\right) \mathrm{m}^{2}=\frac{726}{7} \mathrm{m}^{3} .$$ Height of embankment = $$\left(\frac{\text { Volume }}{\text { Area }}\right)=\left(\frac{704 \times 7}{726}\right) \mathrm{m}=\frac{224}{33} \mathrm{m}=6 \frac{26}{33} \mathrm{m} .$$