Find the number, if six times the number is $12$ .

Divide Rs. $40$ in the ratio $3: 2$.

What is the perimeter of a square whose area is $144 {\mathrm{cm}}^2$ ?

Define tally mark with the help of an suitable example.

How long will it take a boy to go around a regular pentagon of side $17 \mathrm{m}$, at a speed of $5 \mathrm{m}$ per minute ?

Arrange the following decimals in descending order :
$3.35,2.59,28.1,6.0,6.7,3.5$

Solve the equation $5(3 \mathrm{x}+4)-8(6 \mathrm{x}-7)=9 \mathrm{x}-8$.