Correct Answer: 64

Solution : Given, 2a + 3b = 10
Squaring both sides,
(2a + 3b) ² = 10 ²
⇒ 4a ² + 9b ² + 2 × 2a × 3b = 100
⇒ 4a ² + 9b ² + 12ab = 100
⇒ 4a ² + 9b ² + 12(3) = 100
⇒ 4a ² + 9b ² + 36 = 100
⇒ 4a ² + 9b ² = 100 - 36
⇒ 4a ² + 9b ² = 64
Hence, the correct answer is 64.