Question

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?​

Answer 1

Answer:

We have :

(x -5/2) ×8 =3 x

8x- 5/2 ×8 =3 x

8x - 3x = 5/2 × 8 = 20

5x = 20 , x = 20/5 =4 Ans.

Answer 2

Answer:

Given :-

• Anima 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.

To Find :-

• What is the number.

Solution :-

Let,

$\mapsto$ The number that Anima thought be x

$\bigstar$ She subtracts 5/2 from it :

$\implies \sf x - \dfrac{5}{2}$

$\bigstar$ And, again she multiplies that number by 8 :

$\implies \sf 8 \times \bigg(x - \dfrac{5}{2}\bigg)$

According to the question,

$\longrightarrow \sf 8 \times \bigg(x - \dfrac{5}{2}\bigg) =\: 3x$

$\longrightarrow \sf 8x - 8\bigg(\dfrac{5}{2}\bigg) =\: 3x$

$\longrightarrow \sf 8x - \dfrac{40}{2} =\: 3x$

$\longrightarrow \sf \dfrac{16x - 40}{2} =\: 3x$

By doing cross multiplication we get,

$\longrightarrow \sf 16x - 40 =\: 2(3x)$

$\longrightarrow \sf 16x - 40 =\: 6x$

$\longrightarrow \sf 16x - 6x =\: 40$

$\longrightarrow \sf 10x =\: 40$

$\longrightarrow \sf x =\: \dfrac{4\cancel{0}}{1\cancel{0}}$

$\longrightarrow \sf x =\: \dfrac{4}{1}$

$\longrightarrow \sf\bold{\red{x =\: 4}}$

${\small{\bold{\purple{\underline{\therefore\: The\: number\: that\: Anima\: thought\: is\: 4\: .}}}}}$