Find a single equivalent increase if the number is successively increased by 20%, 25% and 30%?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 95%
Successive increases multiply; they do not add, because each increase is taken on the new, larger number.
Assuming the number to be 100:
After the 20% increase: \(100\times1.2=120\)
After the 25% increase: \(120\times1.25=150\)
After the 30% increase: \(150\times1.3=195\)
Single equivalent increase: \(195-100=95\), that is, 95%
Tip: Adding the rates (\(20+25+30=75\%\), Option (1)) leaves out the increase on the earlier increases; for successive changes always multiply the factors.