# percent change (Interesting)

• Nov 28th 2008, 05:16 PM
tinng
percent change (Interesting)
Carmen is 15% lighter than Mary and Thomas is 25% heavier than Carmen. Between Mary and Thomas, who is heavier? By what Percentage?

Solution:
(1) Let Mary weight = 1, Carmen weight =0.85 then Thomas = 0.85*1.25=1.0625
so, Thomas is heavier. He is heavier than Mary by 6.25%

(2) Let Carmen weight = 1 then Mary = 1.15 and Thomas =1.25
so, Thomas is heavier. He is heavier than Mary by 8.7%

Please let me know why there is different anwser?
Thanks so much!!
• Nov 28th 2008, 07:25 PM
2976math
Quote:

Originally Posted by tinng
Carmen is lighter than Mary and Thomas is 25% heavier than Carmen. Between Mary and Thomas, who is heavier? By what Percentage?

Solution:
(1) Let Mary weight = 1, Carmen weight =0.85 then Thomas = 0.85*1.25=1.0625
so, Thomas is heavier. He is heavier than Mary by 6.25%

(2) Let Carmen weight = 1 then Mary = 1.15 and Thomas =1.25
so, Thomas is heavier. He is heavier than Mary by 8.7%

Please let me know why there is different anwser?
Thanks so much!!

============================================
Tinng, I got it.
(2) is correct. if let carmen weight =1.
(1) Carment weight = ( 1/1.15) = 0.869565 then Thomas = 0.869565 * 1.25= 1.0869565
So, Thomas is heavier than Mary by 8.7%.
• Nov 28th 2008, 09:06 PM
tinng
Quote:

Originally Posted by 2976math
============================================
Tinng,
Question is not clear, Carmen is lighter than Mary by how much?

Sorry~~
Carmen is 15% lighter than Mary
• Dec 3rd 2008, 01:42 AM
repcvt
Quote:

Originally Posted by tinng
Carmen is 15% lighter than Mary and Thomas is 25% heavier than Carmen. Between Mary and Thomas, who is heavier? By what Percentage?

Solution:
(1) Let Mary weight = 1, Carmen weight =0.85 then Thomas = 0.85*1.25=1.0625
so, Thomas is heavier. He is heavier than Mary by 6.25%

(2) Let Carmen weight = 1 then Mary = 1.15 and Thomas =1.25
so, Thomas is heavier. He is heavier than Mary by 8.7%

Please let me know why there is different anwser?
Thanks so much!!

The point is (2) Let Carmen weight = 1 then Mary = 1.15
mean mary is heaver than Germen 15%,but not Garmen is lighter than mary 15%, is lighter than mary 0.15/1.15=13%
• Dec 8th 2008, 08:08 AM
Bruce
Quote:

Originally Posted by tinng
Carmen is 15% lighter than Mary and Thomas is 25% heavier than Carmen. Between Mary and Thomas, who is heavier? By what Percentage?

Solution:
(1) Let Mary weight = 1, Carmen weight =0.85 then Thomas = 0.85*1.25=1.0625
so, Thomas is heavier. He is heavier than Mary by 6.25%

(2) Let Carmen weight = 1 then Mary = 1.15 and Thomas =1.25
so, Thomas is heavier. He is heavier than Mary by 8.7%

Please let me know why there is different anwser?
Thanks so much!!

(1) Nice work.

(2) If carmen = 1, then Mary would not be 1.15, as 15% of 1.15 is not 0.15. You would need to find the number which, when 15% of it is taken away, results in 1. But this is not necessary as your first answer is correct.