Answer :
area of the yard is 40 .20 = 800sq ft
time taken = 25 mins
time taken to mow 1sq ft = 25/800 mins
time taken to mow 40 .30 =1200sq ft = ( 25 .1200)/800 = 371/2 mins
thus the extra time taken will be 371/2-25 = 121/2 mins
time taken = 25 mins
time taken to mow 1sq ft = 25/800 mins
time taken to mow 40 .30 =1200sq ft = ( 25 .1200)/800 = 371/2 mins
thus the extra time taken will be 371/2-25 = 121/2 mins