Explanation

• The son's current age be $x$
  
• The man's current age is 5 times the son's age, so the man's age is $5x$.

• Four years ago, the product of their age was 52.

Four years ago:

• The son's age was $x - 4$.
• The man's age was $5x-4$.

According to the problem, the product of their ages 4 years ago is 52:

$$(x-4)(5x-4)=52$$

1. Expand the left side:

   
   

Explanation

Explanation

Explanation

We are given four words:

1. Apparent
2. Apostate
3. Appoint
4. Apparel

Let's arrange them in the order they appear in a dictionary:

• First, compare the first letter of each word (all start with "A").
• Next, compare the second letters:
  • "p" (for "Apparent", "Appoint", "Apparel", "Apostate")
  • Then, compare the third letter:
    • "p" (Apparent, Appoint, Apparel)
    • "o" (Apostate)
  • "Apparel" comes after "Appoint" and before "Apparent"
  • "Appoint" comes after "Apparent"

So, the correct order is:

1. Apparent
2. Apparel
3. Appoint
4. Apostate

Explanation

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211

These are the prime numbers less than 217.

The sum of these prime numbers is 4438. So, the correct answer is (D) None of these.

Explanation

To find the perimeter of a semi-circle, we need to consider two parts:

1. The half of the circumference of the circle, which is $frac{1}{2} times 2pi r = pi r$.
2. The diameter of the circle, which is $2r$.

• The radius $r = 700$ meters.

1. Calculate the curved part (half of the circumference):

   $$text{Curved part} = pi times r = pi times 700 approx 3.1416 times 700 approx 2199.12 , text{m}$$

2. Add the diameter:

   $$text{Diameter} = 2 times r = 2 times 700 = 1400 , text{m}$$

3. Total perimeter:

   $$text{Perimeter} = text{Curved part} + text{Diameter} = 2199.12 , text{m} + 1400 , text{m} = 3599.12 , text{m}$$

4. Convert the result to kilometers:

   $$3599.12 , text{m} = 3.6 , text{km}$$

Explanation

Explanation

Explanation

1. 
   

2. $$a^2 + b^2 = 25 - 12 = 13.$$

Explanation