8th Class Mathematics Related to Competitive Exam Question Bank Mathematical Operations

  • question_answer
    DIRECTIONS: In each of the following questions, three statements of numbers following same rules are given. Find the rule and accordingly find the value of the number? If \[=140+21-8=161-8=153.\]\[6\times 4+2=16\]\[\text{+ and  }\!\!\times\!\!\text{ ,2 and 4}\]then \[\text{+ and  }\!\!\times\!\!\text{ ,2 and 6}\]

    A) 94                   

    B)  \[\text{+ and  }\!\!\times\!\!\text{ ,4 and 6}\]

    C) \[\text{+ and  }\!\!\times\!\!\text{ ,4 and 6}\]                          

    D)  \[4+12=16\]

    Correct Answer: A

    Solution :

        The rule is: Divide each number by 3 and write the quotients in the reverse order. \[8\div 10-3+5\times 6=8\] \[6\times 2+3\div 12-3==15\] \[3\div 7-5\times 10+3=10\] \[=15\times 5+5-20+10\]\[=15\times 5+5-2=75+5-2=78\] \[=8+10\times 3\div 5-6\] etc. \[=8+10\times 3\times \frac{1}{5}-6=8+6-6=8\] \[(3\div 4)+2=2\]\[+\]94.        


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