Suppose Leif can rake his entire yard in 2.5 hours, while his younger sister, Autumn, can do it in 4 hours by herself. How many minutes will it take the two of the to rake the entire yard if they are working together, to the nearest whole number? Please answer in a number of minutes.

1. 93 min2. 123703. 0.17

Step-by-step explanation:

1.

Speed of Leif:

1/2.5 = 2/5 of the job in an hour

Speed of Autumn:

1/4 of the job in an hour

Together their speed is:

2/5 + 1/4 = 8/20 + 5/20 = 13/20

They spend total time for full job:

20/13 hour = 1 7/13 hour = 60 + 7/13*60 min ≈ 93 min

2.

Leaves with red = 5550Leaves with yellow = 6820Leaves with both yellow and red = 4370

Total number

5550 + 6820 = 12370

3.

Total number = 12370Yellow = 6820

Probability of 3 consecutive yellow leaves:

6820/12370*6819/12369*6818/12368 = 0.17 rounded to the nearest hundredths

Ok but uh what do you need with?