The second number must be increased by 100% to equal the first number.

Step-by-step solution

Let the third number be CCC.

For easy calculation, take C=100C=100C=100.

1. Find the two numbers

  • First number is 50% less than CCC:
    A=100−50% of 100=100−50=50A=100-50%\text{ of }100=100-50=50A=100−50% of 100=100−50=50.
  • Second number is 75% less than CCC:
    B=100−75% of 100=100−75=25B=100-75%\text{ of }100=100-75=25B=100−75% of 100=100−75=25.

So:

  • First number A=50A=50A=50.
  • Second number B=25B=25B=25.

2. How much % should the second number be enhanced?

We want to increase BBB so that it becomes equal to AAA.

That is, increase 25 to 50.

Increase needed =50−25=25=50-25=25=50−25=25.

Percentage increase =increaseoriginal value×100=\dfrac{\text{increase}}{\text{original value}}\times 100=original valueincrease​×100.

So:

Percentage increase=2525×100=100%.\text{Percentage increase}=\frac{25}{25}\times 100=100%.Percentage increase=2525​×100=100%.

Therefore, the second number must be enhanced by 100% to make it equal to the first number.

Quick Scoop (story-style intuition)

Think of the third number as 100 coins.

  • The first friend gets 50% less than that, so they hold 50 coins.
  • The second friend gets 75% less, so they hold only 25 coins.

Now you ask: “By what percent should the poorer friend’s 25 coins grow so they also end up with 50 coins?” They need 25 more coins , which is the same as what they already have , so that’s a 100% increase.

TL;DR:
To make the second number equal to the first, increase the second number by 100%.

Information gathered from public forums or data available on the internet and portrayed here.