Question 896197
A=13 copier
B=18 copier
209.67741935483870967741935483871 by 13 A
290.32258064516129032258064516129 by 18 B
209
291

250/13=19.23 min by 13 A
250/18=13.89 min by 18 B

500/18=27.78 500 by 18 B alone
but if we give 209 to 13 A  and 291 to 18 B then it will take about 16 minutes to finish the whole job

Answers:
A)
x/13= t
x= copies to be made by copier a
y/18=T 
y =copies to be made by copier B
B)
200/13=15.4 minutes
C) 
250/13=19.23 min by 13 A
250/18=13.89 min by 18 B

500/18=27.78 500 by 18 B alone
So it is faster using both copiers at the same time. total time taken would be 19.23 minutes since they are working at the same time.

but if we give 209 to 13 A  and 291 to 18 B then it will take about 16 minutes to finish the whole job

13x+18x=500
31x=500
x= abt 16 minutes