Tom,Ted,Tony,Terry worked together on a job.The job paid $500.Each boy was paid according to the amount of work he contributed to the job.Ted and Tony earned $280 together.Ted and Tom have $260,and Ted and Terry got $220.What percent of the job did each boy do?
subtract the second equation from the first
Subtract a) from the last line
but Ted+terry=220 so subtracting
I assume you can take it from here.