Lesson eLearning

A smart chart shows the distance (in km) travelled by a train each day: Day 1 – 120, Day 2 – 150, Day 3 – ?, Day 4 – 210. The average daily distance for the four days is 170 km. What is the missing distance travelled on Day 3?

hard 5 marks Class 5 · Mathematics · Smart Charts
Answer
200 km

The correct answer is 200 km — Therefore, the missing distance travelled on Day 3 is 200 km.

Step-by-step solution

  1. Let the total distance for the four days be T. Since the average is 170 km, T = 4 × 170 = 680 km.
  2. Add the known distances: 120 + 150 + 210 = 480 km.
  3. Subtract the known total from the overall total: 680 – 480 = 200 km.
  4. Therefore, the missing distance travelled on Day 3 is 200 km.
Common mistake: Not accounting for all known distances or mis‑calculating the total

Concept tested: Solving missing value from average in smart chart

Published · How this solution was prepared and checked

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