Using dividend = divisor × quotient + remainder: Number = 11 × 9 + 5 = 99 + 5 = 104

9+8+7+6+5+4+3 = 42.

Then 4+2 = 6.

Wait, let me recalculate: Sum = 42, which reduces to 4+2=6.

The answer should be D.

Actually 9+8+7+6+5+4+3=42, 4+2=6.

Let numbers be 5x and 7x.

Then 5x + 7x = 120, so 12x = 120, x = 10.

Larger number = 7 × 10 = 70

Odd numbers between 10 and 30: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29.

Count = 10

Let number be n.

Then n(n+1) = 342.

Solving: n² + n - 342 = 0.

Using quadratic formula or testing: 17 × 18 = 306 (no), 18 × 19 = 342 (yes).

So n = 18.

Wait, checking: 17 × 18 = 306, 18 × 19 = 342.

Answer is B.

Even numbers from 2 to 50: 2, 4, 6, ..., 50.

This is an AP with first term = 2, last term = 50, common difference = 2.

Number of terms = 25.

Sum = 25(2+50)/2 = 25 × 26 = 650

Let original number = x.

Then x + 25% of x = 500.

So x + 0.25x = 500, 1.25x = 500, x = 400

Let smaller number = x, larger = 2x.

Then 2x - x = 45, so x = 45.

Numbers are 45 and 90.

Let integers be n-1, n, n+1.

Sum = 3n = 81, so n = 27.

The three integers are 26, 27, 28.

Largest = 28

Let tens digit = x, units digit = y.

Then x + y = 12 and 10x + y = 6y + 6.

From second: 10x = 5y + 6.

Substituting y = 12-x: 10x = 5(12-x) + 6 = 60 - 5x + 6.

So 15x = 66, x = 8, y = 4.

Number = 84