Finding the wrong number in a geometric progression series
Question
If a + b means a - b; a - b means a × b; a × b means a ÷ b; a ÷ b means a + b then what is the value of 10 + 30 - 100 × 50 ÷ 25? (Operations are to be replaced simultaneously)
Options
15
0
-15
-25
Explanation
Perform the simultaneous operator substitutions exactly as defined by the encryption rules :
The original expression `10 + 30 - 100 × 50 ÷ 25` transforms into: 10 - 30 × 100 \div 50 + 25.
Now execute the mathematical evaluation strictly following BODMAS order of operations:
The calculation reduces to: 10 - 30 × 2 + 25.
The calculation reduces to: 10 - 60 + 25.
10 - 60 = -50 -50 + 25 = -25.
Answer: (d).
Question details
Year
2024
Paper
CSAT
Question
Q75
Section
Numerical Ability
Sub-topic
Number Series
Type
Factual single
Difficulty
Medium
Source hint
Number series analysis
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