Question

Arun can climb a Coconut tree by 1.5 feet by each lift; however, he slips 0.5 feet every time he makes the next lift. How many individual lifts will he have to reach the top of the Coconut tree of 18.5 feet?

• A. 20
• B. 19
• C. 18
• D. 17

Hint:

When someone slips after each step except the last, subtract one full move (like 1.5 ft) and compute effective climb, then add 1 for the final climb.

Answer 1

The Correct Option is B

Step 1: Effective climb per lift (except the last)
Each time Arun lifts up 1.5 feet but then slips down 0.5 feet.
So effective height gained per lift is: \[ 1.5 - 0.5 = 1 \text{ foot} \] Step 2: Height to climb before final lift
He will not slip after the last lift, so he must reach the last 1.5 feet in the final move.
So, height to cover before the last move is: \[ 18.5 - 1.5 = 17 \text{ feet} \] Step 3: Number of lifts to cover 17 feet (at 1 ft per lift)
\[ 17 \div 1 = 17 \text{ lifts} \] Step 4: Add the final lift (no slip)
Total lifts = \(17 + 1 = \boxed{18}\) Wait! This gives 18 — but let's double-check. After 17 lifts:
Effective height = \(17 \text{ ft}\)
Then, he climbs 1.5 feet on 18th lift → 18 + 1.5 = 19.5?? But tree is only 18.5 ft. That overshoots.
So, we need to stop at **17 feet** before last lift.
Thus: Height reached in 18 lifts (with 17 slips): \[ 17 \times 1 = 17 \text{ ft} \quad \text{(after 17 lifts)}
+ 1.5 \text{ (final lift)} = 18.5 \text{ ft} \] Total lifts: \boxed{18} Correction: Our earlier logic was wrong due to counting the final jump improperly. It should be: \[ 17 \text{ lifts to reach 17 ft} + 1 \text{ final lift to reach 18.5 ft} = 18 \text{ lifts} \] But the question says "individual lifts" including all motion. Wait — here's the trap — the slip happens AFTER the climb. So: Lift 1: Up 1.5 → slips to 1
Lift 2: Up to 2.5 → slips to 2
... Let’s simulate: - After 1 lift: 1 ft - After 2 lifts: 2 ft - ... - After 17 lifts: 17 ft - 18th lift: 18.5 ft → no slip So total = \boxed{18} % Final Answer \[ \boxed{18} \]