Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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Problem C. 816. (September 2005)

C. 816. The price of Aunt Margaret's favourite chocolate has gone up by 30%, while her pension is only raised by 15%. By what percentage will Aunt Margaret's chocolate consumption decrease, if she can only spend 15% more on chocolate.

(5 pont)

Deadline expired on October 17, 2005.


Sorry, the solution is available only in Hungarian. Google translation

Megoldás. Legyen az egységár: a, a vásárolt mennyiség: x, vagyis ax Ft-ot költ csokoládéra Margit néni. Az új egységár: 1,3a, és 1,15ax Ft-ot fog költeni csokoládéra az áremelkedés után. Azaz áremelkedés után a vásárolt mennyiség: {1,15ax\over1,3a}\approx0,8846x.

Vagyis 11,54%-kal csökken a csokoládéfogyasztása.


Statistics:

619 students sent a solution.
5 points:450 students.
4 points:90 students.
3 points:7 students.
2 points:5 students.
1 point:3 students.
0 point:48 students.
Unfair, not evaluated:16 solutions.

Problems in Mathematics of KöMaL, September 2005