The figure shows a grid formed by a collection of unit squares. The unshaded unit square in the grid represents a hole. What is the maximum number of squares without a “hole in the interior” that can be formed within the 4 × 4 grid using the unit squares as building blocks?

The figure shows a grid formed by a collection of unit squares. The unshaded unit square in the grid represents a hole. What is the maximum number of squares without a “hole in the interior” that can be formed within the 4 × 4 grid using the unit squares as building blocks? Correct Answer 20

According to the question, 

Total number of squares = 16

Number of squares without hole,

4 × 4 - 1 = 16 - 1 = 15,

∴ the total number of 1 × 1 squares (without hole) = 15

Now,

the total number of 2 × 2 squares (without hole) = 5

Total number of squares = 15 + 5 = 20

Related Questions

In this question, a passage and a related statement have been given. Read the passage carefully and assess the statement based on it. Using knives and screws, two Russian astronauts on Tuesday took a sample of substance around a mysterious cavity of the spacecraft called the Soyuz, which was placed in the International Space Station, a Moscow official suggested that it was a break - It can also be done. In August, two months after the last visit of the vehicle, the air leak was detected in the Soyuz spacecraft due to the 2 mm air in the ISS. Roskosmos, an astronomical institute, says that cutting off the insulation on the hole and sampling the material around it and the purpose of putting a new insulation on it is to find out that this small but dangerous hole has been done on earth or Is in space. The chief of Roskosmos has said that the error of manufacturing has not been found in the investigation. Experienced astronauts had to struggle but they managed their mission. Before the spacewalk, astronauts were able to inspect the hole just from within the spacecraft. The biggest difficulty was that in the Soyuz spacecraft, the ISS was not designed to improve during adverse weather space, and no railing was also made to catch the space passengers outside the vehicle. Statement: The mysterious hole in the So yuz spacecraft was due to the error of manufacturing. Select the appropriate from the given options A - Statement is completely true B - The statement is possibly true C - the statement can not be determined D - Statement is completely false