After 3 years, the phone value becomes 7600 rupees. The relation between value and years is v = 10000 minus 800t. It represents linear decay because the value decreases by a fixed 800 rupees every year.
A mobile phone is bought for rupees 10,000. Its value decreases by rupees 800 every year. (i) Find the value of the phone after 3 years. (ii) Make a table of values for t varying from 0 to 8 years and show how the value of the phone, v, depreciates with time. (iii) Find an expression that relates v and t and explain why it represents linear decay.
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The mobile phone is bought for 10000 rupees and loses 800 rupees in value every year. After 3 years, the value decreases by 800 multiplied by 3, which equals 2400 rupees. Therefore, the remaining value becomes 10000 minus 2400, which equals 7600 rupees. If t represents the number of years and v represents the value of the phone, then the expression is v = 10000 minus 800t. This represents linear decay because the decrease remains constant every year.
For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 2 Introduction to Linear Polynomials (2026-27):
https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-2/