You are given that "45% of the stamps were issued more than 10 years ago". You are assuming that that same percentage applies to both domestic and foreign stamps. What right do you have to make that assumption?
There is a collection of stamps where 68% are foreign stamps, 45% are issued more than 10 years ago and 30% are foreign stamps issued over 10 year ago.
There are 1200 stamps in total.
How many foreign stamps issued within 10 years?
My solution is (look at the image below):
Attachment 19830
68% of 1200 = 816 which is the total number of Foreign stamps
45% of 1200 = 540 which is the total of 10+ stamps. Therefore 660 are total of foreign stamps issued 10- years.
30% of 660 = 198 which is the foreign stamps issued 10- years.
The answer is : 198
Thank you in advance
Hello, Narek!
Exactly where is your difficulty?
There is a collection of 1200 stamps.
68% are foreign stamps.
45% are issued more than 10 years ago . (This is irrelevant.)
and 30% are foreign stamps issued over 10 year ago ("old").
How many foreign stamps issued within 10 years ("new")?
There are: . foreign stamps.
There are: . foreign stamps which are old.
Therefore, there are: . foreign stamps which are new.
Hello, Narek!
There is a collection of 1200 stamps.
68% are foreign stamps,
45% are issued more than 10 years ago ("old")
30% are foreign stamps issued over 10 year ago.
How many foreign stamps issued within 10 years ("new")?
Place the information in a chart . . .
. .
Complete the chart:
. .
The question is "How many stamps are foreign and new?"
Answer: .
Well, show all 4 solutions to your teacher: it'll prove how unclear he/she is!!
For the record: I'm sure that Soroban's answer of 456 is what's intended.
There are 816 (1200 * .62) F-stamps
There are 360 (1200 * .30) F-stamps > 10y
There are 456 (816 - 360) F-stamps =< 10y
Problem should be clarified, like:
A collection contains 1200 stamps.
68% of the collection are Foreign stamps.
30% of the collection are Foreign stamps > 10 years.
How many Foreign stamps are =< 10 years ?