Two teams of workers were scheduled to produce 680 parts in a month. the first team produced 20% more parts than planned and the second team produced 15% more than planned. the two teams together produced 118 parts more than planned. how many parts was each team supposed to produce according to the plan?

Let
x------> parts produced by the first team according to the plan
y------> parts produced by the second team according to the plan

we know that
x+y=680--------> equation 1
0.20x+0.15y=118--------> equation 2

using a graph tool
see the attached figure

the solution is 
x=320
y=360

the answer is
parts produced by the first team according to the plan------> 320
parts produced by the second team according to the plan----> 360