Question
A girl is standing 5 metres away from a plane mirror.
How much distance should she move towards the mirror so that she will be 2 metres farther from her image?Solution
In a plane mirror, image is formed behind the mirror at the same distance as the object is in front of it. Therefore, if the distance between an object and its image is 2m then object must be 1m ahead of the mirror. The girl should therefore walk 5 – 1 = 4 towards the mirror.
The average age of three children is 20 years. If their ages are in the ratio 3:5:7. Find the age of the youngest child.
2040, 600, 240, 150, ?, 121.875
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