Let the amount of money that is divided be C.
It is divided in the ratio 10 : 7 : 5 among X, Y, Z.
This can be written in another way as X gets 10/ 22 of the amount, Y gets 7/22 of the amount and Z gets 5/22 of the amount.
As Y gets $14 more than Z
(7/22)*C - (5/22)*C = 14
=> C*( 2/ 22) = 14
=> C = 14*11
=> C = 154
The amount that X gets is (10/ 22)*154 = 70
The required value for the total amount is $154 and X gets $70.