Question

Using two lawnmowers and working together Tom and Anne can mow the lawn in 36 minutes. It takes Anne 90 minutes if she mows the lawn herself. How long would it take Tom to do the job working alone?

Answer 1

If Tom takes x minutes, then you need to solve for x in

1/90 + 1/x = 1/36

Answer 2

(1 lawn/36 min)t + (1 lawn/90min)t = 1 lawn

t/36 + t/90 = 1

t/6 + t/15 = 6
t/2 + t/5 = 18

5 t/10 + 2 t/10 = 18

7 t = 180

t = 180/7 = 25.7 minutes
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check
(1/36 + 1/90)25.7 = ?

.0388888... * 25.7

= .99999999.... sure enough

Answer 3

I misread the question