Two numbers are 20% and 65% less than a third number respectively. By what percentage should the second number be increased so that it becomes equal to the first number?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \(128\frac{4}{7}\%\)
Take the third number as 100. A percentage increase is always worked out on the number being increased, here the second number.
First number \(=100-20=80\)
Second number \(=100-65=35\)
Increase needed \(=80-35=45\)
Percentage \(\displaystyle =\frac{45}{35}\times100=\frac{900}{7}=128\frac{4}{7}\%\)
The second number must be increased by \(128\frac{4}{7}\%\).