If a watch is sold at Rs. $60$, there is a loss of $15\%$. For profit of $2\%$, the watch is to be sold at

Find the missing term.

$15 : 20 : : \_\_\_\_ : 16$

(A) $10$
(B) $12$
(C) $14$
(D) $8$

If price of $m$ articles is Rs. $n$, then what is the price of $5$ articles?

(A) $₹\frac{5n}{m}$
(B) $₹\frac{mn}{5}$
(C) $₹\frac{m}{n}$
(D) $₹\frac{5m}{n}$

To complete a work, A takes $50\%$ more than B. If together they take $18$ days to complete the work, how much time will B take to do it?

(A)$30$days
(B)$35$ days
(C) $40$days
(D) $45$ days 

An outlet pipe can empty a cistern in $30$minutes, then what part of the cistern will it empty in $1$ minutes?

(A) $\frac{1}{20}$

(B) $\frac{1}{15}$

(C) $\frac{1}{30}$

(D) $\frac{1}{18}$

Simplify : $(6.5 \times 6.5 - 45.5 + 3.5 \times 3.5)$

Acid Rain destroys vegetation because it contains :

$\sqrt{7+4\sqrt{3}} = ?$

(A) $2+\sqrt{3}$

(B) $\frac{1}{4}+\sqrt{3}$

(C) $2-\sqrt{3}$

(D) $4+\sqrt{3}$