The sum of the series 2 × 1 × 20 4 - 3 × 2 × 20 5 + 4 × 3 × 20 6 - 5 × 4 × 20 7 + + 18 × 17 × 20 20 is equal to:

Unclassified (maths): JEE Main 2025 Mathematics question

JEE Main 2025 · April, Unspecified (session-level dataset) · Q175

JEE Main 2025April, Unspecified (session-level dataset)MathematicsMediumUnclassified (maths)

The sum of the series

2 \times 1 \times \binom{20}{4} - 3 \times 2 \times \binom{20}{5} + 4 \times 3 \times \binom{20}{6} - 5 \times 4 \times \binom{20}{7} + \ldots + 18 \times 17 \times \binom{20}{20}

is equal to:

Your answerInteger or decimal

JEE Main 2025 · April, Unspecified (session-level dataset) · Q175

JEE Main 2025April, Unspecified (session-level dataset)MathematicsMediumUnclassified (maths)

The sum of the series

2 \times 1 \times \binom{20}{4} - 3 \times 2 \times \binom{20}{5} + 4 \times 3 \times \binom{20}{6} - 5 \times 4 \times \binom{20}{7} + \ldots + 18 \times 17 \times \binom{20}{20}

is equal to:

Your answerInteger or decimal