A84
B65
C19
D22
Answer:
A. 84
Read Explanation:
Effect of Transformations on Average
A crucial property of averages, often tested in competitive exams, relates to how they change when each number in a set undergoes a uniform transformation.
General Rule: If every number in a given set of data is subjected to the same arithmetic operation (addition, subtraction, multiplication, or division) by a constant value, the average of the new set of numbers will also be subjected to the same operation by the same constant value.
This means that whatever uniform change is applied to each individual number, the average of the set will reflect that identical change.
Application to Multiplication
In the given problem, the initial average of ten numbers is 7.
Each of these ten numbers is then multiplied by 12.
According to the general rule explained above, if each number is multiplied by a constant (here, 12), the new average will simply be the old average multiplied by that same constant.
Therefore, the new average = Old Average × Multiplier = 7 × 12 = 84.