Find the sum of a number

Question

The sum of a number 3/8 of the number and 5/16 of the number is 7 1/2.  Find the number.

Answer 1

x + (3/8)x + (5/16)x = 7 1/2

 

To combine the left side find lowest common denominator .. 16:

 

(16/16)x + (6/16)x + (5/16)x = 15/2

 

(27/16)x = 15/2

 

x = (15/2)(16/27)

x = 5(8/9)

x = 40/9

x = 4 4/9