Exercise 12 (B) Question 10 - Selina Mathematic Class 6 – Idea of Speed,...

Manoj Agarwal September 18, 2023 0

A distance of $14.4 k m$ covered in $2$ hours $40$ minutes. Find the speed in $m s^{- 1}$ . With this speed, Sakshi goes to her school, $240 m$ away from her house and then returns back. How much time, in all, will Sakshi take?

Distance $= 14.4 k m$
Time taken to cover $= 2 h r s 40 m i n s$
$= 2 . \frac{2}{3}$
$= \frac{8}{3} h r s$

$\Rightarrow$ Speed in m/s $= \frac{1 4 . 4 \times 1 0 0 0}{\frac{8}{3} \times 3 6 0 0 \times 1 0} = \frac{3}{2} m s^{- 1}$
$\Rightarrow$ Distance from house to school and bank $= (240 + 240) m = 480 m$
$\Rightarrow$ Time taken $= \frac{4 8 0}{1 . 5}$ second $= 320$ seconds

$= (\frac{3 2 0}{6 0}) m i n$
$= 50 m i n 20 s e c .$
Hence, the answer is $5 m i n 20 s e c .$