Math New Drill : Level 1 SNS00-0707-L1 Sum of unit fractions

9/10 = 1/X + 1/Y + 1/Z 

X < Y < Z
Find X, Y, and Z.

Answer
X = 2,  Y = 3,  Z = 15

Solution
Since 9/10 > 1/2, X is assumed as 2.

9/10 - 1/2 = 4/10. 

4 = 1 + 3 = 2 + 2 → Not applicable 

4/10 = 8/20. 

8 = 1 + 7 = 2 + 6 = 3 + 5 = 4 + 4 → Not applicable

4/10 = 12/30. 

12 = 1 + 11 = 2 + 10 → Applicable as 10/30 + 2 /30 = 1/3 + 1/15.