Slide37.JPG

Slide38.JPG

  1. Chapter 2 Class 8 Linear Equations in One Variable
  2. Serial order wise
Ask Download

Transcript

Example 19 Present ages of Anu and Raj are in the ratio 4 : 5. Eight years from now the ratio of their ages will be 5:6. Find their present ages. Given that, Present ages of Anu and Raj are in the ratio 4 : 5 (π‘ƒπ‘Ÿπ‘’π‘ π‘’π‘›π‘‘ π‘Žπ‘”π‘’ π‘œπ‘“ 𝐴𝑛𝑒)/(π‘ƒπ‘Ÿπ‘’π‘ π‘’π‘›π‘‘ π‘Žπ‘”π‘’ π‘œπ‘“ π‘…π‘Žπ‘—)=4/5 Let present age of Anu = 4x Years & present age of Raj = 5x years After 8 years from now, Anu’s age = (4x + 8) years Raj’s age = (5x + 8) years Given that, Ratio of ages after 8 years is 5:6 (𝐴𝑛𝑒^β€² 𝑠 π‘Žπ‘”π‘’ π‘Žπ‘“π‘‘π‘’π‘Ÿ 8 π‘¦π‘’π‘Žπ‘Ÿπ‘ )/(π‘…π‘Žπ‘—^β€² 𝑠 π‘Žπ‘”π‘’ π‘Žπ‘“π‘‘π‘’π‘Ÿ 8 π‘¦π‘’π‘Žπ‘Ÿπ‘ )=5/6 (4π‘₯ + 8)/(5π‘₯ + 8)=5/6 By cross-multiplication 6 (4π‘₯ + 8) = 5 (5π‘₯ + 8) (6 Γ— 4)π‘₯+ (6 Γ— 8) = (5 Γ— 5)π‘₯ + (5 Γ— 8) 24π‘₯+ 48 = 25π‘₯+ 40 48 βˆ’ 40 = 25π‘₯βˆ’ 24π‘₯ 8 = π‘₯ π‘₯ = 8 ∴ Present age of Anu = 4π‘₯ = 4 Γ— 8 = 32 years & Present age of Raj = 5π‘₯ = 5 Γ— 8 = 40 Years

About the Author

Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.