Age-related word problems are very common in algebra, particularly in linear equations in one variable for Class 8 mathematics. Let's solve the classic problem: 'Fifteen years from now, Mary's age will be four times her present age. What is Mary's present age?'
This problem tests the ability to convert English statements into algebraic equations.
Always check the answer: If she is 5 now, in 15 years she will be 20. And 20 is exactly four times 5. The answer is verified.
Let Mary's present age be denoted by the variable $x$.
The problem states that after 15 years, her age will be four times her present age. So, we can write the equation as: $x + 15 = 4x$
Therefore, Mary's present age is 5 years.
A linear equation in one variable is an equation that can be written in the form ax + b = 0, where a and b are real numbers and x is a single variable.
1 Metre Mein Kitne Foot Hote Hain?
1 metre = 3.281 feet. 1 foot = 0.3048 metres. Learn the formula to convert metres to feet and feet to metres with examples and a conversion table.
1 Million in Crores — How to Convert Million to Crore
1 million = 0.1 crore = 10 lakhs. 10 million = 1 crore. Learn to convert between international (million, billion) and Indian (lakh, crore) number systems with FAQs.
1 Pavan and 1 Tola — Weight in Grams
Learn what 1 pavan and 1 tola equals in grams. 1 pavan = 8 grams (Kerala gold), 1 tola = 11.664 grams. Traditional Indian gold weight units explained.
How to Convert 1 Second to Millisecond
Learn the exact mathematical conversion of 1 second to millisecond. Understand the metric prefixes, scientific notation, and how to convert larger units of time.
Cube Numbers from 1 to 25 — Complete Table
Memorise cube numbers from 1 to 25. Complete table of n³ values from 1³=1 to 25³=15625 for Class 8 Maths, competitive exams, and quick calculations.
Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.