When all the leaves fallen, a girl can rake the entire yard in 8 hours. when boy does it alone it takes 9 hours how long would it take them to take the yard together? round to the nearest minute

About 20 minutes

Step-by-step explanation:

The original sum: 17

8 + 9 = 17

15 to 19 = round up

hope this helps!!!

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)

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step-by-step explanation: