Avegetable store sold 3 tons of vegetables less on the first day than on the second, and on the third day it sold 5/9 of the amount sold in the first two days. how many vegetables was the store selling every day if it sold altogether 98 tons of vegetables for the three days?

Let
x---------> quantity (ton) of vegetables sold the first day
y---------> quantity (ton)  of vegetables sold the second day
z---------> quantity (ton) of vegetables sold the third day

we know that
x=y-3---------> equation 1
z=(5/9)*(x+y)------> equation 2
x+y+z=98-----> equation 3
substitute equation 2 in equation 3
x+y+[(5/9)*(x+y)]=98----> multiply by 9----> 9x+9y+5x+5y=882
14x+14y=882-----> equation 4

to resolve the equations system formed by
x=y-3
14x+14y=882

using a graph tool
see the attached figure
the solution is
x=30
y=33
x+y+z=98----> z=98-(x+y)----> z=98-63---> 35

the answer is
vegetables sold the first day----> 30 ton
vegetables sold the second day----> 33 ton
vegetables sold the third day------> 35 ton