What approximate value will come in place of the question mark (?) in the…
2025
What approximate value will come in place of the question mark (?) in the following question? (You are not expected to calculate the exact value.)
(35.95)2 − (24.001)2 = ?
- A.
680
- B.
700
- C.
720
- D.
740
Attempted by 1 students.
Show answer & explanation
Correct answer: C
Concept
In an "approximate value" aptitude question, round each decimal to its nearest convenient whole number, then apply the difference-of-squares identity a2 − b2 = (a − b)(a + b) instead of squaring the awkward decimals directly.
Application
Round 35.95 to the nearest whole number: 36.
Round 24.001 to the nearest whole number: 24.
Apply the identity: 362 − 242 = (36 − 24)(36 + 24).
Compute the difference and the sum: 36 − 24 = 12, and 36 + 24 = 60.
Multiply the two results: 12 × 60 = 720.
Cross-check
The unrounded expression evaluates to approximately 716.35, and 720 is the closest of the offered values to this true result, confirming the rounding did not change which value is correct.
Hence, the correct value is 720.