TIMO Khối 7 – Vòng Quốc gia (Heat Round) – Đề số 4

There are 22 pieces of white chopsticks, 18 pieces of yellow chopsticks and 39 pieces of blue chopsticks mixed together. If you want to get 2 pairs of blue chopsticks and 2 pairs of chopsticks which are not blue in the dark, at least how many pieces of chopsticks are needed to be taken?

Pieces of chopsticks: Chiếc đũa; Mixed: Trộn lẫn; Pairs of chopsticks: Đôi đũa; At least: Ít nhất.

A, B, C, D and E are passing balls. Starting from A, 5th time pass will return to B. Within the pass, there is at least 1 time to A, how many passing methods are there? 5th time:

Lần thứ năm;

At least: Ít nhất

Methods: Cách/phương pháp

If 17743 abcd badc + = , calculatea b c d + + + .

Calculate: Tính giá trị