Question

Harper takes 1 minute to read a page of a certain series of history book. There are 400 pages in each of 20 books. The total time taken would be .

• A. $480,000$ seconds
• B. $408,000$ seconds
• C. $840,000$ seconds

Answer 1

The correct option is A $480,000$ seconds

Harper takes $1$ minute ($60$ seconds) to read $1$ page.
Number of pages in each book $=400$

$\therefore$ Harper takes to complete $1$ book
$=(60\times 400)$ seconds

Now, $60\times 400$ can be calculated using long multiplication method as


Hence, Harper takes $24,000$ seconds to complete $1$ book.

Number of history books in the series $=20$

$\therefore$ The time taken by Harper to complete the series of $20$ history books would be $=(24,000\times 20)$ seconds

And, we calculate $24,000\times 20$ using our same long multiplication method.


Hence, the time taken by Harper to complete the entire series of $20$ history books would be $\underset{–}{480,000\text{seconds}}$.