The average height of 39 boys is 159 cm. If the average height of the 47 boys is 173 cm, the average height of the all the boys (in cm) is Options :163.66164.5165.66none of these

To solve this problem, we need to find the total height of all the boys and then divide it by the total number of boys.

Step 1: Find the total height of the 39 boys. The average height of the 39 boys is 159 cm. So, the total height is 39 * 159 = 6201 cm.

Step 2: Find the total height of the 47 boys. The average height of the 47 boys is 173 cm. So, the total height is 47 * 173 = 8121 cm.

Step 3: Find the total height of all the boys. The total height of all the boys is 6201 cm + 8121 cm = 14322 cm.

Step 4: Find the total number of boys. The total number of boys is 39 + 47 = 86 boys.

Step 5: Find the average height of all the boys. The average height of all the boys is the total height divided by the total number of boys. So, the average height is 14322 cm / 86 = 166.53 cm.

So, the average height of all the boys is approximately 166.53 cm. Therefore, the correct answer is "none of these".

To find the average height of all the boys, you need to find the total height of all the boys and then divide by the total number of boys.

Step 1: Find the total height of the 39 boys. The average height of the 39 boys is 159 cm, so their total height is 39 * 159 = 6201 cm.

Step 2: Find the total height of the 47 boys. The average height of the 47 boys is 173 cm, so their total height is 47 * 173 = 8121 cm.

Step 3: Find the total height of all the boys. The total height of all the boys is 6201 cm + 8121 cm = 14322 cm.

Step 4: Find the total number of boys. The total number of boys is 39 + 47 = 86 boys.

Step 5: Find the average height of all the boys. The average height of all the boys is the total height divided by the total number of boys, which is 14322 cm / 86 = 166.53 cm.

So, the average height of all the boys is approximately 166.53 cm. The closest option to this is 165.66 cm, so that would be the answer. However, it's not exactly correct, so the best answer might be "none of these".

To solve this problem, we need to find the total height of all the boys and then divide it by the total number of boys.

First, we find the total height of the first group of boys by multiplying the average height by the number of boys.

159 cm * 39 boys = 6201 cm

Then, we do the same for the second group of boys.

173 cm * 47 boys = 8131 cm

Next, we add these two totals together to get the total height of all the boys.

6201 cm + 8131 cm = 14332 cm

Finally, we divide this total by the total number of boys (39 boys + 47 boys = 86 boys) to find the average height.

14332 cm / 86 boys = 166.65 cm

So, the average height of all the boys is 166.65 cm. The closest option to this is 165.66 cm, but this is not exactly correct. So, the correct answer is "none of these".