Optimization

Optimization

By Thương Trần

Chiếc thuyền chỉ chở được người đàn ông và thêm một trong ba vật: sói, cừu hoặc cải bắp. Nếu chỉ có sói và cừu ở với nhau thì sói sẽ ăn thịt cừu. Nếu chỉ có cừu và cải bắp ở với nhau thì cừu sẽ ăn cải bắp. Hãy giúp người đàn ông tìm cách chở tất cả qua sông với số lượt di chuyển ít nhất.​

By Thương Trần

Chở cừu qua sông

Lượt 1

Để cừu ở lại và quay về.

Lượt 2

Chở sói qua sông.

Lượt 3

Để sói ở lại

Chở cừu về.​

Lượt 4

Chở bắp cải qua sông.

Lượt 5

Để sói với bắp cải ở lại rồi quay về

Lượt 6

Chở cừu qua sông.

Lượt 7

Fill in the Blanks

A father elephant has 5 babies at the different age levels: 5 months, 6 months, 7 months, 8 months, 9 months old. He wants to bring his babies across the river where crocodiles live.

Each time crossing the river, he can take only two babies with him. But he won't let two babies who are one-month different together on a bank because they always arguing. How many turn at least will he need to take all his five babies across the river so that they will be not arguing?

given that each time he travel from one bank to the other one is counted as a turn.

Fill in the Blanks

Mrs Mary has two-plate scale balance and two weights of 2kg and 3kg.

She only has a 13kg salt bag. At least how many times of weighing will she need to get exactly 7kg of salt? Given that she can slowly pour salt in two scale plates.

Fill in the Blanks

Mr Jane has three oil cans: 8-liter can, 5-liter can and 3-liter can. In which, the 8-liter can is full of oil, two other cans are empty. At least how many times of pouring oil will she need to get 4 liters of oil? Given that she has no more equipment, except those three cans.

Open Ended

Mrs. Anna puts apples and mangoes in carton boxes for selling. One carton box can be filled with 9 apples and 4 mangoes; or with 6 apples and 6 mangoes. If she wants to fill a carton box with apple only, what is the most number of apples can be filled in the carton box?

Given that the size of apples is similar to each other and so does the size of the mangoes.

Open Ended

Four kids Max, Alex, Swan and Emma get lost on a mysterious island and they are chased by aboriginals. They run to a bridge which can bear the mass of two kids as maximum. Given that it takes Max 1 minute, Alex 2 minutes, Swan 5 minutes and Emma 8 minutes to cross the bridge. Every two kids who cross the bridge need one kid to come back and lead the other. At least, how many minutes does it take all four kids across the bridge?