Question

A ship can cover a certain distance in $10$ hours at a speed of $16$ nautical miles per hour. By how much should its speed be increased so that it takes only $8$ hours to cover the same distance? (A nautical mile in a unit of measurement used at sea distance or sea water i.e., $1852$ metres)

Answer 1

Speed $=\frac{Distance}{Time}$

$\Rightarrow$ Distance = speed $\times$ time

Since it is given that the distance travelled will be the same .

$D_1=D_2$

$S_1=16$ nautical miles per hour.

$t_1=10$ hours

$S_2=?$ $t_2=8$ hours

$S_1\times t_1=S_2\times t_2$

$\Rightarrow 16\times 10=S_2\times 8$

$S_2=\frac{16\times 10}{8}=20$ nautical miles per hour.

So the ship has to increase its speed from $16$ to $20$ natical miles per hour .

$\Rightarrow$ It has to increase its speed by "$4$ nautical miles per hour"