DoUBT: 5lb book, Page 651 chapter 18 R&W Ques. 18

[saurb007]

Q: If 45 people built 1/2 of a pyramid in 288 days, how many days did it take 65 people to build the next 1/6 of the pyramid, rounded to the nearest integer, assuming each person works at the same constant rate?

As mentioned in the ques. 1/2 of a pyramid has been built and calculate time required to built NEXT 1/6 of the pyramid. Then
NEXT 1/6 of pyramid should be = 1/2*1/6 = 1/12.

(it would be 1/6th of the remaining 1/2 of a pyramid).

But in the solution provided in book, the value taken is 1/6.

Could you please clarify the doubt. (or is it a error in the book).

Thanks!
Saurabh

[tommywallach]

Hey Saurb,

I'm afraid you're misreading here. You're thinking if it said:

"How long would it take to build 1/6th of what remains to be built?"

But it doesn't say that. Consider this difference.

I ate half the pizza. How long will it take you to eat the next half?

I ate half the pizza. How long will it take you to eat half of what's left?

See the difference? In the first example, we're just dealing with half the pizza. In the second example, we're dealing with one-quarter of the pizza. In the pyramid question, it just says "the next 1/6th" which clearly isn't referring to 1/6th of what's left.

Hope that helps!

-t

[saurb007]

Hey Tom,

Thank you man, for clarifying the doubt.
Above example helped me to think clearly.

Cheers!

[tommywallach]

Glad to help! : )

-t