Question

A landscaping company needs

Answer 1

Let 
x--------> volume of 35​% fertilizer
y--------> volume of 25​% fertilizer

we know that
x+y=220-----> x=220-y-----> equation 1
x*0.35+y*.25=220*.29-----> equation 2

substitute equation 1 in equation 2
[220-y]*0.35+0.25*y=63.8----> 77-0.35*y+0.25*y=63.8
0.10*y=13.2------> y=13.2/0.10----> y=132 gal
x=220-y----> x=220-132----> x=88 gal

the answer is
88 gal of 35​% fertilizer
132 gal 25​% fertilizer