The average of ten numbers is 7. If each number is multiplied by 12, then the average of the new set of numbers is :
A. 7
B. 19
C. 82
D. 84
Answer: Option D
Solution(By Examveda Team)
Average of 10 numbers = 7Sum of these 10 numbers = (10 × 7) = 70
$$\eqalign{ & \therefore {x_1} + {x_2} + ..... + {x_{10}} = 70 \cr & \Rightarrow 12{x_1} + 12{x_2} + ..... + 12{x_{10}} = 840 \cr & \Rightarrow \frac{{12{x_1} + 12{x_2} + ..... + 12{x_{10}}}}{{10}} = 84 \cr} $$
⇒ Average of new numbers is 84
Join The Discussion
Comments ( 1 )
Related Questions on Average
A. 125 km/hr
B. 75 km/hr
C. 135 km/hr
D. 120 km/hr
Number increase 70*12= 840
New avg = 840/10= 84