Bony takes 2 hours to wash 500 dishes, and Farah takes 3 hours to wash 450 dishes. How long will they take working together to wash 1000 dishes?
সমাধান
সঠিক উত্তর: Option C
Ben washes 500 dishes / 2 hours = 250 dishes / 1 hour.
Frank washes 450 dishes / 3 hours = 150 dishes / 1 hour.
dishes that Frank washes in x hours + dishes that Ben washes in x hours = 1000 dishes
250x + 150x = 1000
400x = 1000
x = 2.5