A walks from his house to his daughter-s school a speed of 3 km-hr and returns a speed of 4 km-hr- If he takes 21 minutes the double journey- the distance between his house and the school-2-7 km3-4 km0-6 km1-6 km

Question

Toppr Admin · Accepted Answer

Let the distance between house and school -D kmSince- Time -DistanceSpeedD3-D4-21607D12-2160D-35-0-6km

A man walks from his house to his daughter's school at a speed of 3 km/hr and returns at a speed of 4 km/hr. If he takes 21 minutes for the double journey; find the distance between his house and the school.
2.7 km
3.4 km
0.6 km
1.6 km

Let the distance between house and school $= D$ km

Since, Time $= \frac{D i s t a n c e}{S p e e d}$
$\frac{D}{3} + \frac{D}{4} = \frac{21}{60}$

$\frac{7 D}{12} = \frac{21}{60}$

$D = \frac{3}{5} = 0.6 k m$

A man walks from his house to his daughter's school at a speed of 3 km/hr and returns at a speed of 4 km/hr. If he takes 21 minutes for the double journey; find the distance between his house and the school.2.7 km3.4 km0.6 km1.6 km

Let the distance between house and school =D kmSince, Time =DistanceSpeedD3+D4=21607D12=2160D=35=0.6km

A man walks from his house to his daughter's school at a speed of 3 km/hr and returns at a speed of 4 km/hr. If he takes 21 minutes for the double journey; find the distance between his house and the school.
2.7 km
3.4 km
0.6 km
1.6 km

Let the distance between house and school $= D$ km

Since, Time $= \frac{D i s t a n c e}{S p e e d}$
$\frac{D}{3} + \frac{D}{4} = \frac{21}{60}$

$\frac{7 D}{12} = \frac{21}{60}$

$D = \frac{3}{5} = 0.6 k m$