Directions: In the following question, a number sequence is given with one term missing. Choose the correct term that will continue the same pattern and replace the question mark in the given sequence.45,54,47,?,49,56,51,57,53
Correct answer: C. 55
- A. 48
- B. 50
- C. 55
- D. 60
Explanation
The sequence 45, 54, 47, ?, 49, 56, 51, 57, 53 can be divided into two interleaved patterns. For the odd-positioned numbers, the pattern is 45, 47, 49, 51, 53, increasing by 2 each time. The even-positioned numbers form the pattern 54, ?, 56, 57. Here, the numbers increase by 1 each time. Therefore, the missing term must be 55 to maintain this sequence.Option C (55) is the correct answer, as it fits the even-positioned pattern of increasing by 1. The other options do not fit the observed pattern and hence are incorrect.
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Atoms emit or absorb light at specific wavelengths because electrons occupy quantized energy levels and change levels by absorbing or releasing photons. The topic covers emission and absorption spectra, spectral series, hydrogen’s line spectrum, energy-level transitions, and the relation between wavelength, frequency and photon energy.
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