🚀 Middle School
| IGCSE • Mathematics

Simultaneous

Elimination.

1 Lesson 1 MCQ 1 Mnemonic
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Lesson

Simultaneous — Lesson

1) Hook — The Cricket Match Puzzle 🏏

Imagine a thrilling cricket match between India and Australia. The Indian team scored a total of 250 runs in 40 overs. The openers, Rohit Sharma and Shubman Gill, together scored 150 runs. Rohit scored 10 more runs than Shubman. Can you find out how many runs each player scored?

To solve this, we need to find two numbers that add up to 150 and differ by 10 — this is where simultaneous equations come in handy!

2) Core Concepts — What are Simultaneous Equations?

Simultaneous equations are a set of two or more equations with multiple variables that are solved together because the variables are related.

For example, if we have two variables, x and y, simultaneous equations look like:

Equation 1: x + y = 150
Equation 2: x - y = 10

Here, x could be Rohit's runs, and y could be Shubman's runs.

How to Solve Simultaneous Equations?

  • Method 1: Substitution — Solve one equation for one variable and substitute into the other.
  • Method 2: Elimination — Add or subtract equations to eliminate one variable.

Example using Elimination:

x + y = 150
x - y = 10

Add both equations:

(x + y) + (x - y) = 150 + 10

2x = 160

x = 80

Now substitute x = 80 into the first equation:

80 + y = 150

y = 150 - 80 = 70

Answer: Rohit scored 80 runs and Shubman scored 70 runs.

3) Key Formulas / Rules

Simultaneous Equations General Form:

a₁x + b₁y = c₁

a₂x + b₂y = c₂

Elimination Method:

  • Multiply equations if needed to make coefficients of x or y equal.
  • Add or subtract equations to eliminate one variable.
  • Solve for the remaining variable, then back-substitute.

4) Did You Know? 🤔

Simultaneous equations are used in Bollywood movie scripts too! When choreographing dance moves, choreographers use simultaneous equations to calculate timings and steps so that dancers move perfectly in sync — just like solving for multiple variables to keep everything balanced!

5) Exam Tips — Score High with These Tricks!

  • Write equations carefully: Translate word problems step-by-step to avoid mistakes.
  • Check signs (+/-): A common error is mixing up positive and negative signs.
  • Choose the easiest method: If coefficients are simple, elimination is quick; otherwise, substitution might be better.
  • Always verify your solution: Substitute values back into both equations to confirm correctness.
  • Practice typical board questions: Problems involving age, money, speed, and cricket scores are popular in IGCSE exams.
2
MCQ Practice

Simultaneous — Mcq

3
Memory Trick

Simultaneous — Mnemonic

Mnemonic 1: SIMULTANEOUS = “Solve It, Match Up, Let’s Try All Numbers To Answer Neatly, Every Option Under Study” 🧩

This phrase helps you remember the steps for solving simultaneous equations: Solve the equations, Match variables, Try substitution or elimination, and Answer Neatly by checking all options.

Mnemonic 2: “Simultaneous Equations का Solution है Team Work!” 🤝

  • S - Substitute one equation into another
  • I - Identify variables
  • M - Multiply if needed to align coefficients
  • U - Use elimination or substitution
  • L - Look for the value of one variable
  • T - Then find the other
  • A - Always check your answers
  • N - Note down solutions clearly
  • E - Equation solved!

Just like a cricket team works together to win, simultaneous equations need teamwork between methods! 🏏

Mnemonic 3: Hindi Rhyming Trick 🎶

“दो समीकरण, दो अनजाने, मिलकर करें हल, न हो कोई फसाने!”

(“Two equations, two unknowns, solve together, no confusion!”)

Remember: जब दो unknowns हों, simultaneous equations से solution पाएं। Like Bollywood heroes teaming up for a blockbuster hit! 🎬✨

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