The weight of ball A is 20 kg. It is 2/3 times lighter than ball B.What is the weight of the ball B
Answers
Step-by-step explanation:
- make 3 sets of balls
Set A- ball (1,2,3)
Set B- ball (4,5,6)
Set C- ball (7,8)
Now weight Set A and Set B
Case 1- If weight of Set-A and Set-B are equal, means the ball with different weight is in Set-C.
- Take one ball from Set-C (let say ball 7) and replace it with ball 1
- Again weight the Set-A (7,2,3) and Set-B (4,5,6) again
- If the weight of two sets are still equal means ball 8 is the ball with different weight else ball 7 is the ball with different weight.
Case 2- If the weight of Set-A and Set-B are not equal (let say Set-A is heavier). Means one of the ball in Set-A is either heavy or one ball in Set-B is lighter than others. And balls in Set-C are of equal weight.
- Now after the first weight we know that the Set-A is heavy.
- Make new Set: Set-A (balls 1,7,8) , Set-B (2,5,6) and Set-C (3, 4) and weight again.
- If the direction of the scale changes then ball 2 is the ball with different weigh
- till here every thing is fine , now if we are allowed to use a little trick ( swapping the balls while we are weighing it) there will be 2 cases either the direction of the scale will remain same or it will balance.
- If the scale is balance replace ball 3 with 1 if the scale is still balance ball 4 is the result else ball 3 is the result.
- if the scale remains in the same position replace ball 6 with ball 7 and ball 5 with ball 4. If the scale is now balance ball 5 is the result , if it remains in the same position ball 1 i