Question

if the mean of 2x,5,3x,12,5x,17 and 6 is 20 then x=___​

Answer 1

(2x+5+3x+12+5x+17+6) ÷7=20

10x+40=20×7

10x+40=140

10x=140-40

10x=100

x=10

Answer 2

A/Q,

$\frac{2x + 5 + 3x + 12 + 5x + 17 + 6}{7} = 20 \\ = > \frac{10x + 40}{7} = 20 \\ = > \frac{10(x + 4)}{7} = 20 \\ = > x + 4 = \frac{20 \times 7}{10} \\ = > x + 4 = 2 \times 7 \\ = > x + 4 = 14 \\ = > x = 14 - 4 \\ = > x = 10$