Question 1195457
Very much like the other example.  See that one and learn.

1000 ml available of 70%
x  ml of diluent


x, amount of diluent
d, amount of 70% dextrose
x+d=50
d=50-x


Question asks for x, how much diluent.

{{{70*(50-x)+0*x=5*50}}}
Solve this for x.