Skip to content

Lesson eLearning

A fire extinguisher is rated to discharge 120 kg of extinguishing agent in 15 s. If it is used for 9 s, how much agent is discharged?

medium 1 mark Class 8 · Science · Combustion and Flame

Answer

72 kg

The correct answer is 72 kg — Multiply rate by 9 s: $8 \times 9 = 72$  kg.

Step-by-step solution

Find discharge rate: $120 kg \div 15 s = 8 kg s^{- 1}$ .
Multiply rate by 9 s: $8 \times 9 = 72$  kg.

Common mistake: Using rate as 8 kg s⁻¹ instead of 8 kg per 15 s

Concept tested: Proportional discharge rate of fire extinguisher

Published 13 October 2026 · How this solution was prepared and checked

← All Combustion and Flame questions