Question

Reemu reads 1/5th pages of a book. If she reads further 40 pages, she would have read 7/10th page of the book. How many pages are left to be read.​

Answer 1

Answer:

There are 24 pages left to be read.

Step-by-step-explanation:

Let the total number of pages of the book be x.

We have given that,

Reemu reads ( 1 / 5 )ᵗʰ pages of the book.

$\displaystyle{\therefore\sf\:Reemu\:reads\:\dfrac{1}{5}\:\times\:x\:pages}$

$\displaystyle{\implies\sf\:Reemu\:reads\:\dfrac{x}{5}\:pages}$

From the given condition,

$\displaystyle{\sf\:\dfrac{x}{5}\:+\:40\:=\:\dfrac{7}{10}\:\times\:x}$

$\displaystyle{\implies\sf\:\dfrac{x\:+\:40\:\times\:5}{5}\:=\:\dfrac{7x}{10}}$

$\displaystyle{\implies\sf\:\dfrac{x\:+\:200}{\cancel{5}}\:=\:\dfrac{7x}{\cancel{10}}}$

$\displaystyle{\implies\sf\:x\:+\:200\:=\:\dfrac{7x}{2}}$

$\displaystyle{\implies\sf\:2\:(\:x\:+\:200\:)\:=\:7x}$

$\displaystyle{\implies\sf\:2x\:+\:400\:=\:7x}$

$\displaystyle{\implies\sf\:7x\:-\:2x\:=\:400}$

$\displaystyle{\implies\sf\:5x\:=\:400}$

$\displaystyle{\implies\sf\:x\:=\:\cancel{\dfrac{400}{5}}}$

$\displaystyle{\implies\underline{\boxed{\red{\sf\:x\:=\:80}}}}$

Now,

$\displaystyle{\sf\:Pages\:read\:by\:Reemu\:=\:\dfrac{7x}{10}}$

$\displaystyle{\implies\sf\:Pages\:read\:by\:Reemu\:=\:\dfrac{7\:\times\:\cancel{80}}{\cancel{10}}}$

$\displaystyle{\implies\sf\:Pages\:read\:by\:Reemu\:=\:7\:\times\:8}$

$\displaystyle{\implies\boxed{\pink{\sf\:Pages\:read\:by\:Reemu\:=\:56}}}$

Pages left to be read = Total pages of book - Pages read by Reemu

⇒ Pages left to be read = 80 - 56

⇒ Pages left to be read = 24

∴ There are 24 pages left to be read.

Answer 2

(｡◕‿◕｡)

Answer

• Let the total number of pages of the books be x..
• Given,
• Reemu reads ( 1 / 5 )th pages of the books..

Reemu reads 1 / 5 × (x pages)

→ Reemu reads x / 5 pages..

From the given condition,

$☞ \: \frac{x}{5} + 40 = \frac{7}{10} \times x \\ ☞ \: \frac{x + 40 \times5 }{5} = \frac{7x}{10} \\ ☞ \: \frac{x + 200}{5} = \frac{7x}{10} \\ ☞ \: x + 200 = \frac{7x}{2} \\ ☞ \: 2(x + 200) = 7x \\ ☞ \: 2x + 400 = 7x \\ ☞ \: 7x \: - 2x \: = 400 \\ ☞ \: 5x = 400 \\ ☞ \: x = \frac{400}{5} \\ ☞ \: x = 80$

• Now,
• Pages read by Reemu = 7x / 10

➜ Pages read by Reemu = 7 × 80 / 10

➜ Pages read by Reemu = 7 × 8

➜ Pages read by Reemu = 56

➜ Pages left to read = Total pages of book / Pages read by Reemu

➜ Pages left to be read = 80 - 56

➜ Pages left to be read = 24

There are 24 pages left to be read..