Ex 2.4, 1 Amina thinks of a number and subtracts 5/(2 ) from it. She multiplies the result by 8. The result now obtained is 3 times the same number she thought of. What is the number? Let the number Amina thought be 𝑥
Given that,
She Subtracts 5/2 from it, i.e. 𝑥−5/2
& Multiplies results by 8
∴ New number = 8 (𝑥−5/2)
Also, Given,
New number = 3 × Old number
8 (𝑥−5/2)=3𝑥
8𝑥−8 ×5/2=3𝑥
8𝑥−4 ×5=3𝑥
8𝑥−20=3𝑥
8𝑥=3𝑥+ 20
8𝑥−3𝑥=20
5𝑥=20
𝑥=20/5
𝑥 = 4
∴ The number Amina thought = x = 4.

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.