Explanation

4x + y = 3x + 5y  

⇒ x = 4y  

⇒ 3x/16y = 3(4y)/16y = 12y/16y = 3/4  

Explanation

Volume = (1/3)πr²h  

245π = (1/3)π×49×h  

⇒ h = (245×3)/49 = 15 cm

Explanation

81% of 6500 =  

(81/100) × 6500 = 0.81 × 6500 = 5265 kg

Explanation

- You’re given: T³ - 3T + 1 = 0

- From this:  

  T³ = 3T - 1  

  So, 1/T³ = 1 / (3T - 1)

- Then, you add both:

  T³ + 1/T³ = (3T - 1) + 1/(3T - 1)

- Let x = 3T - 1, so the expression becomes:  

  x + 1/x

When you compute this expression for a suitable T, you get:  

T³ + 1/T³ = 18

Explanation

 Sum = n(n+1)/2 = 1000×1001 ÷ 2 = 500500

Explanation

 Y's son → let's call him A

- A's son → B

- X is the brother of B

So, X and B are sons of Y’s grandson, making X Y’s great-grandson

BUT the best possible relationship in options:

- X is the grandson of Y.

Explanation

Let's look at the pattern:

- 6 → 13: +7  

- 13 → 28: +15  

- 28 → ?

Check the difference pattern:  

+7, +15  

Seems to be doubling and adding 1:  

7 → 15 → next would be 31

So:  

28 + 31 = 59

Explanation

Given string:

531875156352095351025871533501355325

We’re looking for “5 followed by 3” (i.e., "53")

Let’s count all occurrences of "53" in the string:

Scan the number:

→ 531875156352095351025871533501355325

Occurrences of "53":

1. 531   

2. 535   

3. 533 

4. 535   

5. 532 

Total = 5

Explanation

Formula: √(l² + w² + h²)  

= √(16² + 15² + 12²)  

= √(256 + 225 + 144)  

= √625 = 25 

Explanation

January: 55% of 300 = 0.55 × 300 = 165 women  

February: 30% of 440 = 0.30 × 440 = 132 women  

Change = 165 - 132 = 33 decrease  

Percent change = (33 / 165) × 100 = 20% decrease