Question

4.4. A weight lifter increases his body mass by 15% after some heavy training. His new body mass is 78 kg. He claims that he has gained approximately 10 kg of weight after the training session. State whether his claim is valid or not by showing all the necessary calculations.​

Answer 1

Explanation:

We can start by finding the weight lifter's original body mass before the training session:

Let x = original body mass

Then, we know that 15% of x is equal to 78 kg - x:

0.15x = 78 - x

1.15x = 78

x = 78/1.15

x ≈ 67.83 kg

Therefore, the weight lifter's original body mass was approximately 67.83 kg.

Now, let's find the difference between the weight lifter's new body mass and his original body mass:

78 kg - 67.83 kg ≈ 10.17 kg

So, the weight lifter did indeed gain approximately 10 kg of weight after the training session. Therefore, his claim is valid.