Answer:
a = 16
Step-by-step explanation:
The median is the middle value of the data arranged in ascending order.
If there is no exact middle then the median is the average of the 2 values either side of the middle
a + 1 , 2a - 1 , a + 7 , 3a + 4
↑ middle
Then
[tex]\frac{2a-1+a+7}{2}[/tex] = 27 ( multiply both sides by 2 to clear the fraction )
3a + 6 = 54 ( subtract 6 from both sides )
3a = 48 ( divide both sides by 3 )
a = 16
