Explanation

The mixture contains 12% copper, which means that 12% of the mixture's weight is copper.

We want to find out how many kg of mixture is required to get 69 kg of copper.

Let's say the weight of the mixture is x kg.

Since 12% of the mixture is copper, the weight of copper in the mixture is 12% of x, which is 0.12x.

We are told that the weight of copper is 69 kg, so we can set up the equation:

0.12x = 69

To solve for x, we can divide both sides by 0.12:

x = 69 / 0.12

x = 575

So, the weight of the mixture is 575 kg.

Explanation

Explanation

Mean of 5 numbers =18

⇒ Sum of these 5 numbers =18×5=90

Let number that has been excluded be x

New mean =490−x​=16

Solving this, we get

90−x=64

∴x=26

Explanation

To evaluate this expression, we can simplify the fraction:

12.1 ÷ 19.8 = 0.61 (approximately)

11/18 = 0.61 (approximately)

Explanation

Let's break this down step by step:

1. Let the man's monthly income be x.
2. He spends Rs. 3500 per month, which means his savings are x - 3500.
3. He saves 12 ½% of his income, which can be written as a decimal: 0.125x.
4. Since his savings are equal to his income minus his expenses, we can set up the equation: 0.125x = x - 3500.
5. Simplify the equation: 0.125x = x - 3500 --> 0.125x - x = -3500 --> -0.875x = -3500.
6. Divide both sides by -0.875: x = 3500 / 0.875 --> x = 4000.

So, the man's monthly income is Rs. 4000.

Explanation

Average of a , b = ( a + b ) /2

16a + 16b = 48

a + b = 3  || divide each term by 16

The average is ( a + b ) / 2 = 3/2

= 1.5

Explanation

Let's add the numbers:

4 + 4.44 = 8.44

8.44 + 44.4 = 52.84

52.84 + 4.04 = 56.88

56.88 + 444 = 500.88

So, the correct answer is: 500.88

Explanation

Let's break this down step by step:

1. Let Ali's current age be A and Zia's current age be Z.
2. Since Ali is younger than Zia by 10 years, we can write an equation: A = Z - 10
3. We know that 5 years back, their ages were in the ratio 1:2. So, we can set up another equation based on their ages 5 years back: (A-5)/(Z-5) = 1/2
4. Cross-multiply and simplify the equation: 2A - 10 = Z - 5
5. Substitute the expression for A from step 2 into the equation in step 4: 2(Z-10) - 10 = Z - 5
6. Simplify and solve for Z: 2Z - 20 - 10 = Z - 5 --> Z = 25

So, Zia is currently 25 years old.

Explanation

Sum of m numbers = mn^2

Sum of n numbers = nm^2

∴ Average of (m + n) numbers

= mn(m+n)/(m+n)

= mn

Explanation

To find the fourth proportional, we need to set up a proportion:

60 : 48 :: 30 : x

Where x is the fourth proportional.

We can rewrite this as: 60/48 = 30/x

Cross-multiplying, we get: 60x = 30 × 48

Simplifying, we get: 60x = 1440

Dividing both sides by 60, we get: x = 24

So, the fourth proportional is 24.