Question

7. A car can finish a certain journey in 10 hours at the speed of 48 km/hr. By how much should its
speed be increased so that it may take only 8 hours to cover the same distance.
8. A school has 8 periods a day each of 45 minutes duration. How long would each period be, if the
school has 9 periods a day, assuming the number of school hours to be the same?​

Answer 1

7.Given:-

A car can finish a certain journey in 10 hours

At the speed of 48 km/hr

To Find:-

Let the increased speed be x km/h.

Time 10 Hours or 8hours

Speed (km/h) 48x+48

10 × 48 = 8 (x + 48)

$\sf \: \longrightarrow 480x = 8× + 384 \\ \\ \sf \: \longrightarrow 8x= 480 -384 \\ \\ \sf\longrightarrow 8x = 96 \\ \\ \sf \sf\longrightarrow \underline{\boxed{\purple{ \: \: 1 \: \: \: }}}$

Thus, the speed should be increased by 12km/h.✅