Explanation

Let C.P. of each article be Re. 1 C.P. of x articles = Rs. x

S.P. of x articles = Rs. 20

Profit = Rs. (20 - x)

∴20−xx×100=25⇒2000−100x=25x125x=2000⇒x=16

Explanation

Looking at the given numbers, we can see that they are all prime numbers.

- The next prime number after 41 is 43. So, the missing number in the series is 43.

Therefore, the completed series is: 11, 13, 17, 19, 23, 29, 31, 37, 41, 43.

Additional information:

- Prime numbers are natural numbers greater than 1 that have no positive divisors other than 1 and themselves.

Explanation

To find the new price, you need to calculate 20% of the original price and subtract that amount from the original price.

Original price = $20

Discount = 20% of $20 = 0.20 x $20 = $4

New price = Original price - Discount

= $20 - $4

= $16

So, the correct answer is: $16.

Explanation

x + y = 67 ... (equation 1)

x - y = 3 ... (equation 2)

where x and y are the two numbers.

We can solve this system of equations by adding equation 1 and equation 2, which eliminates y:

2x = 70

Dividing both sides by 2 gives:

x = 35

Now that we have x, we can substitute it into equation 1 to find y:

35 + y = 67

Subtracting 35 from both sides gives:

y = 32

So, the two numbers are 35 and 32.

Explanation

Four years ago, the average age of A, B, and C was 25 years.

This means that the total age of A, B, and C four years ago was 25 x 3 = 75 years.

Since then, all three have aged 4 years, so their total age now is 75 + 4 + 4 + 4 = 87 years.

Five years ago, the average age of B and C was 20 years.

This means that the total age of B and C five years ago was 20 x 2 = 40 years.

Since then, both B and C have aged 5 years, so their total age now is 40 + 5 + 5 = 50 years.

Now, we know that the total age of A, B, and C is 87 years, and the total age of B and C is 50 years.

So, A's current age is 87 - 50 = 37 years.

The correct answer is: 37 years

Explanation

To solve this proportion, we can use the following steps:

Write the proportion as a fraction: 3/x = 12/20

Cross-multiply: 3 × 20 = 12 × x

Simplify: 60 = 12x

Divide both sides by 12: x = 60/12

Simplify: x = 5

So, the value of x is 5.

Explanation

Five years ago, the average age of P and Q was 15 years.

This means that the total age of P and Q five years ago was 15 x 2 = 30 years.

Since then, both P and Q have aged 5 years, so their total age now is 30 + 5 + 5 = 40 years.

The average age of P, Q, and R today is 20 years, so the total age of P, Q, and R is 20 x 3 = 60 years.

We already know that the total age of P and Q is 40 years, so R's age must be 60 - 40 = 20 years.

After 10 years, R's age will be 20 + 10 = 30 years.

So, the correct answer is: 30 years

Explanation

To find the total strength now, you need to calculate 12% of the original strength and add it to the original strength.

Original strength = 550

Increase = 12% of 550 = (12/100) × 550 = 66

New strength = Original strength + Increase = 550 + 66 = 616

So, the total strength now is 616.

Explanation

To evaluate this expression, we need to follow the order of operations (PEMDAS):

Multiply the numerators (numbers on top):

1 × 3 × 6 = 18

Multiply the denominators (numbers on the bottom):

10 × 5 × 5 = 250

Write the result as a fraction:

18/250

Simplify the fraction by dividing both numbers by their greatest common divisor (GCD), which is 2:

18 ÷ 2 = 9

250 ÷ 2 = 125

So, the simplified result is:

9/125

Explanation

x + x1/5 = 60000

x = 50000

So increase = 60000 - 50000 = 10,000