A sports club has 15,000 members. In the first year the number rises by 10%; in the second year it falls by 20%, and in the third year it rises by 5%. How many members does it have at the end of the three years?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 13,860
Each year’s change is on the value at the start of that year, so the yearly factors are multiplied.
Factors: \(1.1\), \(0.8\) and \(1.05\)
\(15000\times1.1\times0.8\times1.05=13860\)
At the end it has 13,860 members.
Why the other options are incorrect
Option (1) 14,250 — Incorrect. This adds the changes into a single fall of 5%; each change is on the value at the start of that year.
Option (2) 13,200 — Incorrect. This leaves out the third year.
Option (3) 11,340 — Incorrect. This takes the first year’s change the wrong way.