olymmath

HK-PC 2019

Hong Kong Preliminary Selection Contest and TST 2019.

Other problems

Problem 5

Is it is possible to choose 24 distinct points in the space such that no three of them lie on the same line and choose 2019 distinct planes in a way that each plane passes through at least 3 of the chosen points and each triple belongs to one of the chosen planes?

Problem 6

If 57a+88b+125c≥114857a + 88b + 125c \geq 1148 , where a,b,c>0a,b,c > 0 , what is the minimum value of a3+b3+c3+5a2+5b2+5c2?a^3 + b^3 + c^3 + 5a^2 + 5b^2 + 5c^2?