Explanation

Multiply 10 x 12 x 15 = 1800

ND16-3-2023

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

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

Explanation

Since the student who left weighed 45 kgs, the total weight of all 60 students (including the student who left) is 59x + 45.

When the student left, the average weight of the remaining 59 students increased by 200g (or 0.2 kgs), so we can set up the equation:

59x + 45 = 60(x - 0.2)

Simplifying the equation, we get:

59x + 45 = 60x - 12

Solving for x, we get:

x = 57

So, the correct answer is: 57