Explanation

(a + b) – (a – b)  

= a + b – a + b  

= 2b

Explanation

 (Using identity a² - b² = (a - b)(a + b)):  

(100 - 99)(100 + 99) = 1 × 199 = 199

Explanation

2x + 5 = 3 

2x= 3 - 5 

2x = -2 

x = -1

Explanation

  - Percent means “per hundred”.  

  - 1.5% of 100 = (1.5/100) × 100 = 1.5

Explanation

7 days × 24 hours = 168 hours

Explanation

- Cross product formula:  

  (a, b) × (c, d) = (ad - bc) (since 2D vectors give a scalar representing the magnitude and direction along the z-axis)

- Calculation:  

  (1)(-1) - (0)(0) = -1 - 0 = -1

Explanation

 1. Fuel for Rs. 450  

= 450 ÷ 90 = 5 liters

2. Distance per 15 liters = 2 km  

→ Distance per 1 liter = 2 ÷ 15 = 0.133 km

3. Distance for 5 liters = 0.133 × 5 = 0.665 km

4. Convert to meters:  

0.665 km = 665 meters

Explanation

- 100 → 98 (-2)  

- 98 → 94 (-4)  

- 94 → 88 (-6)  

- 88 → 80 (-8)  

- 80 → 70 (-10)  

Following the same pattern:  

70 – 12 = 58

Explanation

Bloons fly in the air, the reason is low-density

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Balloons that float are typically filled with helium gas, 

Helium gas is less dense than the gas in our air. 

When the air inside the balloon is heated, the molecules in the air begin to move around and spread out,

The air in balloon becomes less dense.

Explanation

- cos(90°) = 0  

- So, sin(θ) × cos(90°) = sin(θ) × 0 = 0