Elisa can do a job in 5 hours thus her rate is 1/5 job per hour

Elisa and Lori can do the same job in 2 hours thus their together rate is 1/2 jobs per hour

Lori can do a job in x hours thus her rate is 1/x jobs per hour

1/5 + 1/x = 1/2

by solving we find

x = 10/3

x = 3 hr 20 min

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Lori needs 3 hr 20 min to do the same job alone.